ZXCTN 6120H-S V5.10.00 Product Description - 20220424 - EN

ZXCTN 6120H-S V5.10.
00
Product Description
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ZXCTN 6120H-S V5.10.00Product Description

Version Date Author Reviewer Remark
V1.0 2021/05/30 ZTE ZTE The first draft
© 2022 ZTE Corporation. All rights reserved.

ZTE CONFIDENTIAL: This document contains proprietary information of ZTE and is not to be disclosed or used
without the prior written permission of ZTE .
Due to update and improvement of ZTE products and technologies, information in this document is subjected to
change without notice.
ZTE Confidential & Proprietary 3

TABLE OF CONTENTS
1 Product Positioning............................................................................................................................... 9
2 Product Features.................................................................................................................................... 9
3 System Architecture............................................................................................................................ 10
3.1 Equipment Switching Capability............................................................................................... 10
3.2 Interface Type and Quantity...................................................................................................... 10
3.3 Physical Performance.................................................................................................................11
3.4 System Architecture....................................................................................................................12
3.4.1 System Hardware Architecture...................................................................................13
3.4.2 System Software Architecture.................................................................................... 15
3.4.3 Control System Architecture....................................................................................... 15
4 Functions and Features......................................................................................................................16
4.1 Multiservice Transport Capability............................................................................................. 16
4.1.1 Ethernet Service............................................................................................................16
4.2 FlexE Functions...........................................................................................................................17
4.3 L2 Functions.................................................................................................................................18
4.3.1 Ethernet Basic Functions.............................................................................................18
4.3.2 VLAN and VLAN Extension Features........................................................................18
4.3.3 Link Aggregation (LAG)............................................................................................... 19
4.3.4 STP Functions............................................................................................................... 19
4.3.5 DHCP Relay...................................................................................................................20
4.3.6 Multicast..........................................................................................................................20
4.4 L3 Functions.................................................................................................................................20
4.4.1 L3 Basic Functions....................................................................................................... 20
4.4.2 L3 Routing Protocols.................................................................................................... 22
4.4.3 IPv6 Related Functions................................................................................................22
4.5 MPLS.............................................................................................................................................22
4 ZTE Confidential & Proprietary

4.5.1 Overview of MPLS........................................................................................................ 22
4.5.2 MPLS Network Architecture........................................................................................ 23
4.5.3 MPLS Basic Functions................................................................................................. 23
4.5.4 LDP..................................................................................................................................24
4.5.5 RSVP-TE........................................................................................................................ 24
4.6 MPLS L2 VPN..............................................................................................................................25
4.7 BGP/MPLS L3 VPN.................................................................................................................... 26
4.8 EVPN.............................................................................................................................................27
4.9 SDN............................................................................................................................................... 27
4.10 SR................................................................................................................................................ 28
4.10.1 Segment Routing MPLS............................................................................................ 28
4.10.2 SR Architecture........................................................................................................... 28
4.10.3 SR-BE........................................................................................................................... 29
4.10.4 SR-TE........................................................................................................................... 29
4.10.5 Segment Routing IPv6...............................................................................................29
4.11 Network Slicing..........................................................................................................................31
4.11.1 Network Slicing Architecture.....................................................................................31
4.11.2 Slicing based on FlexE.............................................................................................. 31
4.12 Ultra-low Latency...................................................................................................................... 32
4.13 Multicast Routing Protocol.......................................................................................................32
4.14 QoS Features............................................................................................................................ 33
4.15 OAM Features........................................................................................................................... 34
4.15.1 Ethernet OAM..............................................................................................................34
4.15.2 MPLS OAM.................................................................................................................. 36
4.15.3 SR OAM....................................................................................................................... 36
4.15.4 Slicing Channel OAM................................................................................................. 36
4.15.5 BFD............................................................................................................................... 36
4.16 Telemetry....................................................................................................................................37
4.17 Protection Features.................................................................................................................. 37
4.17.1 Device Level Protection.............................................................................................37

4.17.2 Network Level Protection.......................................................................................... 38
4.17.3 Access Link Protection.............................................................................................. 39
4.17.4 Other Protection Mode...............................................................................................40
4.18 SQM............................................................................................................................................ 40
4.18.1 RFC 2544/Y.1564....................................................................................................... 40
4.18.2 TWAMP........................................................................................................................ 40
4.19 Synchronization Feature..........................................................................................................41
4.20 Safety Features......................................................................................................................... 42
4.20.1 AAA ID Authentication............................................................................................... 42
4.20.2 Network Security.........................................................................................................43
5 Technical Indexes and Specifications............................................................................................44
5.1 Interface Indexes.........................................................................................................................44
6 Networking Application...................................................................................................................... 47
7 Operation and Maintenance.............................................................................................................. 47
8 Environmental Indexes....................................................................................................................... 47
8.1 Storage..........................................................................................................................................47
8.2 Transportation..............................................................................................................................49
8.3 Operation...................................................................................................................................... 51
9 Abbreviation...........................................................................................................................................53

FIGURES
Figure 3- 1 ZXCTN 6120H-S architecture..............................................................................................12
Figure 3- 2 ZXCTN 6120H-S Sub-rack structure..................................................................................13
Figure 3- 3 ZXCTN 6120H-S slot distribution ......................................................................................14
Figure 3- 4 ZXCTN 6120H-S functional units........................................................................................14
Figure 3- 5 Distributed routing operating system..................................................................................15
Figure 3- 6 ZENIC ONE controller architecture.................................................................................... 16
Figure 4- 1 FlexE architecture..................................................................................................................17
Figure 4- 2 MPLS network architecture..................................................................................................23
Figure 4- 3 BGP/MPLS VPN network architecture...............................................................................26
Figure 4- 4 SR mechanism....................................................................................................................... 29
Figure 4- 5 Overview of Network slicing ...............................................................................................31
Figure 4- 6 Slicing channel cross connection........................................................................................32
Figure 6- 1 ZXCTN 6120H-S application scenario............................................................................... 47
TABLES
Table 3- 1 ZXCTN 6120H-S switching capacity....................................................................................10
Table 3- 2 ZXCTN 6120H-S service interface types............................................................................10
Table 3- 3 ZXCTN 6120H-S auxiliary interface type and number..................................................... 11
Table 3- 4 Physical performance list.......................................................................................................11
Table 4- 1 EVC (Ethernet Virtual Connection) service supported by ZXCTN 6120H-S................ 16
Table 4- 2 VLAN feature........................................................................................................................... 18
Table 4- 5 ZXCTN 6120H-S Ethernet OAM function........................................................................... 35
Table 4- 6 ZXCTN 6120H-S Ethernet link OAM functions.................................................................. 35
Table 5- 1 GE optical interface performance indexes..........................................................................44
Table 5- 2 10GE optical interface performance indexes..................................................................... 45

Table 5- 5 100GE optical interface performance indexes...................................................................46
Table 8- 1 Climate requirements for equipment storage..................................................................... 48
Table 8- 2 Concentration requirements for mechanically active substances.................................. 49
Table 8- 3 Concentration requirements for chemically active substances.......................................49
Table 8- 4 Requirements for climate .....................................................................................................49
Table 8- 5 Concentration requirements for mechanically active substances ................................ 50
Table 8- 6 Concentration requirements for chemically active substances .....................................50
Table 8- 7 Requirements for temperature and humidity ....................................................................51
Table 8- 8 Other climate environment requirements ..........................................................................51
Table 8- 9 Concentration requirements for mechanically active substances.................................. 52
Table 8- 10 Concentration requirements for chemically active substances ...................................52

1 Product Positioning
ZXCTN 6000 is ZTE's new generation product of metro optical transmission for packet
transmission. It is mainly applied in the access layer of metro transport network. It is the
transport network equipment for most kinds of services such as mobile communication and
enterprise customers.
ZXCTN 6120H-S is the 1U high integrated device, located at access layer of mobile
metropolitan transport network. Facing the complexity and uncertainty of service network
carrier requirements, it combines the advantages of packet and transport technology, adopts
packet switching as the core architecture, integrates multi-service adapter interface, VPN,
synchronous clock, carrier-level OAM, protection and other functions. On the basis of that, the
processing and transmission of Ethernet is achieved.
ZXCTN 6120H series fully considers the 4G network supplement construction, 5G low
frequency, 5G high frequency scene. As the most competitive 1RU product, ZXCTN 6120H-S
can provide 25GE/50GE/100GE Ethernet interfaces for 5G high frequency scene and high
density of 10GE interfaces for the first two scenarios, nicely satisfying long term network
evolution from LTE to 5G.
2 Product Features
 Transmit various standard services such as 3G/4G/5G.
 Support 10GE/25GE/50GE/100GE large bandwidth solutions.
 System architecture supports low latency forwarding based on Flexible Ethernet (FlexE)
and ultra-high precision time synchronization.
 Adopt SDN architecture to make the network programmable and intelligent.
 The integrated 1RU device is suitable for various installation environments such as
cabinets (300mm-depth ), wall-mounted, indoor and outdoor cabinets.
 Carrier-class and network-level protection ensure the reliability of service transport.
 Green energy-saving design provides high efficiency, environmental protection and

saves operation cost.

3 System Architecture
3.1 Equipment Switching Capability
ZXCTN 6120H-S supports the packet-based service switching.
The service switching capacity is shown in Table 3-1.
Table 3- 1 ZXCTN 6120H-S switching capacity
Service Processing ZXCTN 6120H-S
Switching capacity 1000Gbps
Access capacity 1050Gbps
Packet forwarding rate 453Mpps
Interface : 4*100GE/50GE+8*25GE/10GE+14*25GE/10GE/GE+10*10GE/GE
3.2 Interface Type and Quantity
ZXCTN 6120H-S supports multiple types of Ethernet interfaces, as shown in Table3-2.
Table 3- 2 ZXCTN 6120H-S service interface types
Type Description Remark
FE interface Optical interface:100BASE-FX UNI
Electrical interface: 1000BASE-TX

GE interface UNI/NNI
Optical interface: 1000BASE-SX, 1000BASE-LX, 1000BASE-ZX
10GE interface Optical interface: 10GBASE-SR, 10GBASE-LR, 10GBASE-ER UNI/NNI
25GE interface Optical interface: 25GBASE-LR, 25GBASE-ER UNI/NNI
50GE interface Optical interface: 50GBASE-LR, 50GBASE-ER, 50GBASE-ZR UNI/NNI
Optical interface: 100GBASE-LR4, 100GBASE-ER4,

100GE interface UNI/NNI
100GBASE-ZR4

ZXCTN 6120H-S also supports NM interface, clock interface and alarm interface, debugging
interface as shown Table 3-3.
Table 3- 3 ZXCTN 6120H-S auxiliary interface type and number
Auxiliary interface Quantity Parameter Remark
RJ45 physical
LCT interface 1 Support 1x LCT interface
interface
External alarm RJ45 physical

1 Support 4x external alarm input/output
input/output interface interface
RJ45 physical
BITS 1 Support 2M BITS/Hz input/output.
interface
Support 1PPS+TOD interface RJ45 physical

GPS interface 2
(input or output). interface
3.3 Physical Performance

Table 3- 4 Physical performance list
Attribute Description
Sub-rack mm (width x height x

depth) (not including mounting 442*43.6*270
Equipment physical
flange)
dimensions
Sub-rack mm (width x height x
482.6*43.6*270
depth) (including mounting flange)
Weight In full configuration 5kg
Total slot number Fixed

Slot number
Service slot Fixed
Power supply condition (DC) -48V +/- 20%
Rated current (DC) 10A
Power supply Typical power consumption 160W
Maximum power consumption 350W
Fuse specification 20A

-40°C ~ +65°C
Operating environment temperature ( 50GE/100GE interface only
support -5°C ~ +55°C )
Storage environment temperature -40°C ~ +70°C
Environment requirements Relative humidity of working

5%~95%, non-congealing
environment
Noise <63dB
Resist the earthquake magnitude

Earthquake resistance
scale of 9
MTBF >400000 hours
MTTR <0.5 hour
Equipment reliability Reliability >=99.999%
Redundancy backup
1+1 redundancy
for power supply
Heat dissipation Heat load in full configuration 1134BTU/hr
3.4 System Architecture
ZXCTN 6120H-S system architecture consists of data plane, control plane and management
plane. The data plane includes several modules such as packet switching, Slicing Ethernet
cross connection, OAM, protection, QoS and synchronization. The control plane includes
routing, signaling, and resource management modules. The data plane and control plane are
connected to other devices via UNI and NNI. The management plane can also be connected
to other devices via management or service interface. ZXCTN 6120H-S system architecture
is shown in Figure 3-1:
Figure 3- 1 ZXCTN 6120H-S architecture

3.4.1 System Hardware Architecture
3.4.1.1 Overall of Hardware Architecture
ZXCTN 6120H-S adopts the large-capacity rack design. The hardware system includes
chassis,fan module, power module, control/switch unit.
Dimension of XCTN 6120H-S is 442mm (width ) * 43.6mm (height) * 270mm (depth). The
width meets industry standards. The device can also be installed into the IEC297 standard
cabinet or ETSI standard cabinet.
 Sub-rack
Sub-rack structure and slot description: ZXCTN 6120H-S Sub-rack adopts control/switch/
clock/service area, power board area. As it is shown in the figure below.
Figure 3- 2 ZXCTN 6120H-S Sub-rack structure
 Slot distribution
ZXCTN 6120H-S integrates control/switch/service units, power supply boards and Fans.

Figure 3- 3 ZXCTN 6120H-S slot distribution
It has the following functions:
 Power board area: Inserted with 2 DC power boards.
 Control/switch/clock/service area: Inserted with control, switch,clock and communication

processing units, auxiliary interface.
3.4.1.2 Working Principle of Hardware System
ZXCTN 6120H-S uses a centralized switching architecture.
After the normal service flow is processed by physical-layer chip, the packet is directly sent to
control/switching chip and then to the corresponding board port through the switching network.
For example, before special service information such as 1588 PTP or OAM packets sent to
the switching network, the board itself pre-processes the packets and then sends them to the
main switching chip to determine whether the service is terminated or forwarded as a final
result.
Figure 3- 4 ZXCTN 6120H-S functional units

3.4.2 System Software Architecture

Figure 3- 5 Distributed routing operating system
ROSNG software architecture design breaks through the integrated software design solution
of the traditional embedded system, and its software system supports dynamic loading
module. The entire ROSNG software system runs in a micro-kernel operating system. System
kernel resources run in the highest-level privileged mode. The application protocols and
service function components of the system run in the lower level privileged mode. The failure
of this application would not destroy the kernel resources, achieving upper and lower isolation
between kernel and application. Meanwhile, each application separately runs in independent
user state spaces, which are also separated from each other. The illegal operation of the
program in one process and the out-of-bounds modification will not damage other application
processes, enabling the separation between the left and right.
3.4.3 Control System Architecture
The entire network system is divided into Application Plane, Orchestration Plane, Controller
Plane, and Forwarding Plane from top to bottom.
 Application layer is mainly related to the service application, such as the L2VPN service,
the L3VPN service, and the traffic optimization. The APP server converts the service
requirement of the user side to the operation primitive through the RESTCONF interface,
and sends it to the orchestration layer.
 Orchestration layer transmits it to the control layer through the RESTCONF interface in a
finer granularity. The control layer can be divided into single-domain controllers,
multi-domain, multi-layer , multi-vendor controllers.

 After the internal calculation of the controller layer, it is sent to the forwarding plane
through the SBI, affecting network devices.
Figure 3- 6 ZENIC ONE controller architecture
Traditional BOSS system on the left and the SDN orchestration system in the middle perform
end-to-end service orchestration and coordination and jointly manage the network to support
compatibility and evolution of existing networks. The performance collection management
system module on the left collects and analyzes network performance, and interacts with the
SDN orchestration system to monitor and optimize the network.
4 Functions and Features
4.1 Multiservice Transport Capability

In a packet transport network, service types mainly include Ethernet services.
4.1.1 Ethernet Service
ZXCTN 6120H-S accesses and transmits Ethernet services via 10GE, 25GE, 50GE, 100GE
Ethernet interfaces.
ZXCTN 6120H-S offers the following Ethernet service interfaces compliant with ITU-T and
MEF6.
Table 4- 1 EVC (Ethernet Virtual Connection) service supported by ZXCTN 6120H-S
Service types Port-Based VLAN-Based

Service types Port-Based VLAN-Based
E-Line EPL EVPL
E-LAN EP-LAN EVP-LAN
E-Tree EP-Tree EVP-Tree
4.2 FlexE Functions
FlexE technology adds a FlexE Shim layer between RS (Regenerator Section) and PCS
(Physical Coding Sublayer) of the IEEE802.3 protocol stack, separating the service logic layer
from the physical layer. By bonding multiple PHY links, it transmits much more Ethernet
service traffic. Thus, logical layer can implement link bonding, sub-rate, channelized and
other functions as well as network slicing.
Slicing channel cross connection (SC-XC) is an end-to-end(E2E) networking-level technology

by reusing FlexE shim layer which can reduce forwarding latency through the cross of FlexE
bit blocks. In the SC-XC E2E packet forwarding network, PE node supports statistical
multiplexing based on packet forwarding and P node supports SC-XC to allow L1 flow switch.
Figure 4- 1 FlexE architecture
FlexE consists of FlexE Client, FlexE Shim and FlexE Group.
 FlexE Client : 64/66B Ethernet code streams support n*5G rates.
 FlexE Shim : Sublayer between the Mac/RS and PCS/PHY layers performs multiplexing
and demultiplexing between FlexE Client and FlexE Group.
 FlexE Group : A group of bonded FlexE PHYs
FlexE functions:
 Link bonding : It provides a large transport pipeline by bonding multiple FlexE PHYs.

 Channelized : Data of different clients are transmitted via different time slots of one or
more PHYs.
4.3 L2 Functions
4.3.1 Ethernet Basic Functions
ZXCTN 6120H-S supports the following Ethernet basic functions:
 Support port full-duplex working mode.
 Support port rate, duplex mode, flow control and MTU user configuration.
 Support the following L2 switching functions:
 MAC address learning
 MAC address binding
 MAC address filtering
 Support ingress and egress port mirroring
 Support storm suppression of broadcast / unknown multicast / unknown unicast packets:
 Based on port
 Controlled by percentage or rate
 Support up to 9K-byte Jumbo frame.
 Support LLDP link-layer discovery defined by 802.1ab.
4.3.2 VLAN and VLAN Extension Features
ZXCTN 6120H-S supports powerful VLAN functions to divide virtual working groups.
Table 4- 2 VLAN feature

VLAN Support VLAN based on port and MAC address.
Support QinQ-based forwarding.

VLAN Features
QinQ Support ordinary QinQ and port-based external label.
Support selective QinQ and flow-based external label.

Support selective QinQ internal priority mapping

Support TPID modification
Support 1:1, 1:2 and 2:1 QinQ functions
ZXCTN 6120H-S supports port-based VLAN. Access, Trunk and Hybrid interfaces are
provided according to whether the packets sent and received by the interface are
encapsulated with VLAN Tags.
In order to extend the address space of the VLAN ID and improve security, ZXCTN 6120H-S
extends the VLAN based on IEEE802.1Q, namely QinQ. QinQ, also known as single stacked
VLAN or dual VLAN, encapsulates the VLAN tag of private network into the VLAN tag of
public network, so that these packets can pass through the backbone network (public network)
of operators with two layers of VLAN tags. Since QinQ has two layers of labels, it extends the
VLAN range of the metro backbone networks.
4.3.3 Link Aggregation (LAG)
ZXCTN 6120H-S supports link aggregation which technically binds a group of physical
interfaces. These interfaces are logically act as one link.
Link aggregation is a way to increase bandwidth and improves reliability by binding physical
links. Link aggregation can increase bandwidth between different devices, increasing link
transmission flexibility and redundancy. When some links of the link aggregation group(LAG)
failed, the link aggregation function can protect the transmission of faulty link and switch the
service to the working link of the same link aggregation group, thereby significantly improving
the transmission reliability.
ZXCTN 6120H-S implements not only manual load sharing link aggregation, but also Link
Aggregation Control Protocol (LACP) defined by IEEE 802.3ad. It supports interface binding,
MAC/VLAN/IP-based load balancing.
4.3.4 STP Functions
ZXCTN 6120H-S supports the Spanning Tree Protocol (STP) conforming to the IEEE802.1D,
the Rapid Spanning Tree Protocol (RSTP) conforming to the IEEE802.1w, and the Multiple
Spanning Tree Protocol (MSTP) conforming to the IEEE802.1s.
To ensure the topology stability of the L2 switching network, ZXCTN 6120H-S uses BPDU,

Root, loop and other protection mechanisms. ZXCTN 6120H-S provides a port-based
protocol closing function.
4.3.5 DHCP Relay
DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses to hosts.

After obtaining the IP address, the host can initiate IP communication through the IP address.
In the LTE phase, DHCP is required to dynamically assign addresses to eNB to improve the
automation of the network.
ZXCTN 6120H-S supports DHCP (Dynamic Host Configuration Protocol) Relay function.
DHCP Server is usually deployed in aggregation-layer or core-layer devices, thus it is
required that the DHCP packet of the host can penetrate different sub-nets to reach the
DHCP server. In order to support penetration, the ZXCTN 6120H-S can snoop and relay the
DHCP packets.
4.3.6 Multicast
ZXCTN 6120H-S supports IGMP proxy/snooping multicast:
 Support IGMP v2/v3.
 Support static multicast table configuration.
 Support IGMP proxy/snooping-based multicast table establishment, and then forward

multicast services according to service ports included in the multicast table.
 When IGMP proxy/snooping is enabled, the multicast table that has been created is sent
according to the specified port of the multicast table. Unknown multicasts can be discarded or
broadcasted according to the configuration.
 Support dynamic establishment, deletion and maintenance of multicast tables based on

VPLS/E-LAN services and multicast query.
4.4 L3 Functions
4.4.1 L3 Basic Functions
 L3 interface

ZXCTN 6120H-S supports the following L3 interfaces:
 Ethernet-based L3 interface
 VLAN-based L3 interface
 QinQ-based L3 interface
 ARP
ZXCTN 6120H-S supports ARP (Address Resolution Protocol). Basic function of ARP is to
query the MAC address of the target device based on the IP address to ensure smooth
communication.
 Support dynamic ARP request
 Support ARP answer
 Support dynamic ARP aging. The aging time can be set
 Support static ARP configuration
 IPv4 unicast routing and forwarding
ZXCTN 6120H-S supports IPv4 unicast routing and forwarding:
 Support IPv4 unicast routing full-rate forwarding.
 Support IPv4 basic unicast routing and forwarding.
 Support best matching of hardware routing table .
 IPv6 unicast routing and forwarding
ZXCTN 6120H-S supports IPv6 unicast routing and forwarding:
 Support IPv6 unicast routing full-rate forwarding.
 Support IPv6 basic unicast routing and forwarding.
 Support best matching of hardware routing table.
 Static route
 ECMP
 ICMP
 UDP

 TCP
4.4.2 L3 Routing Protocols
ZXCTN 6120H-S supports the following routing protocols:
 OSPF
 ISIS
 BGP
4.4.3 IPv6 Related Functions
ZXCTN 6120H-S supports the following IPv6 related functions:
 ICMPv6
 IPv6 static route
 ISISv6
 OSPFv3
 BGP4+
 IPv6/IPv4 stacks
 6vPE
4.5 MPLS
4.5.1 Overview of MPLS
In order to improve the forwarding speed of the router, Multi-protocol Label Switching (MPLS)
is proposed first. Currently, the MPLS is developing for backbone router and VPN solutions.
MPLS combines powerful L3 routing function of IP network and efficient forwarding

mechanism of traditional L2 network, and adopts connection-oriented mode in the forwarding
plane, which is similar to existent L2 forwarding mode. This enables MPLS to easily realize
seamless convergence of IP and L2 network, such as Ethernet. MPLS can also provide better
solutions for Traffic Engineering (TE), Virtual Private Network (VPN) and Quality of Service

(QoS). Therefore, MPLS has become an important standard for data network scale expansion
and operability improvement.
4.5.2 MPLS Network Architecture
Typical MPLS network architecture is shown below. The basic element of MPLS network is
Label Switch Router (LSR). The network domain formed by LSRs is called MPLS domain.
LSRs located at the edge of MPLS domain and connected to other networks are called a
Label Edge Router (LER), and LSRs in MPLS domain are called core LSR. If the LSR has
one or more neighbors that do not run the MPLS, the LSR is the LER. If all neighboring nodes
of the LSR run the MPLS, the LSR is the core LSR.
Figure 4- 2 MPLS network architecture
ZXCTN 6120H-S can work as an LSR and LER.
4.5.3 MPLS Basic Functions
MPLS system architecture of ZXCTN 6120H-S conforms to the standard : Multi-protocol Label
Switching Architecture (RFC 3031).
ZXCTN 6120H-S's tag stack structure conforms to the standard: MPLS Label Stack Encoding
(RFC 3032).
ZXCTN 6120H-S supports the following basic MPLS functions:
 Tag space management of each platform
 Domain management of static/dynamic tags
 Ingress node service and label processing

 Export node service and label processing
 Intermediate node tag processing
 Tag stack nesting
4.5.4 LDP
MPLS system has multiple label distribution protocols. LDP (Label Distribution Protocol) is
one of the basic signaling of the MPLS. It is mainly used to establish and maintain LSP/PW. It
is the most commonly used LSP/PW signaling protocol in the current network. In a hybrid
network including ZXCTN 6120H-S and traditional IP/MPLS routers, LDP LSPs are
established by interconnecting LDP and IP/MPLS routers in existing networks.
 Release and management of LDP LSP labels
ZXCTN 6120H-S supports the following LDP label distribution and management mode
combinations: downstream autonomous mode (DU) + Independent tag control mode
(Independent) + liberal tag retention mode (Liberal).
 LDP LSP creation
ZXCTN 6120H-S supports the binding of FECs and labels through LDP, and notifies the
bindings to neighboring LSRs of the LSP to establish LSPs.
 LDP MD-5 certification
ZXCTN 6120H-S supports MD-5 encryption and is compliant with RFC 3036.
4.5.5 RSVP-TE
Resource Reservation Protocol (RSVP) is designed for the integrated service model and used
for resource reservation of LSP nodes. The RSVP works on the transport layer but does not
participate in application data transfer. It is a network control protocol similar to the ICMP.
The extended RSVP of ZXCTN 6120H-S can support the distribution of MPLS labels and
carry resource reservation information when transmitting label binding information. The
extended RSVP is called RSVP TE and is used to establish a LSP tunnel as a signaling
protocol to implement the following functions:
 TE LSP establishment and maintenance
 TE LSP path removal

 Error notification
 Explicit path function
 Support the following basic functions of RSVP TE defined in relevant standards:
 Support RSVP soft state mechanism
 Support FF (Fixed Filtering style) and SE (Shared Explicit) resource reservation
types of RSVP TE.
 Support basic message and processing mechanism of RSVP.
 Support RSVP TE defined message and processing mechanism supporting RSVP
extension to establish TLS-LSP
 Support TE LSP establishment through RSVP-TE.
 Support LSP maintenance and summary refreshing.
4.6 MPLS L2 VPN
ZXCTN 6120H-S supports multiple forms of services and supports perfect L2 VPN
technology.
L2 VPN is a VPN based on link-layer technologies. ZXCTN 6120H-S supports the MPLS L2
VPN technology whose features are as follows:
 Support VPLS/VPWS
 Support LDP L2 VPN
 Support H-VPLS
 Support L2 VPN multicast
 Support MS-PW
 Support PW status notification

4.7 BGP/MPLS L3 VPN
ZXCTN 6120H-S follows the RFC4364 protocol, and L3 VPN by using BGP/MPLS VPN
technology. The basic network architecture is as follows:
Figure 4- 3 BGP/MPLS VPN network architecture
ZXCTN 6120H-S supports VRF forwarding instances. Each route is allocated with VRF tag.
 L3 VPN access
ZXCTN 6120H-S accesses L3 VPNs in multiple modes, including common IP services,

VLAN-based IP services and VPWS/VPLS termination to L3 VPNs.
 L3 VPN tunnel
ZXCTN 6120H-S can adopt the following three methods to pre-create LSP tunnels between
PEs:
 Use SR-TE and RSVP-TE as the signaling protocols and support traffic engineering.
 Use SR-BE and LDP as the signaling protocols, but not support traffic engineering.
 Use static tunnels manually configured on the management plane.
 Customer route learning and publishing
ZXCTN 6120H-S can learn customer network routes in the following ways:
 Static route
 OSPF
 ISIS

 BGP
 VPN FRR
ZXCTN 6120H-S supports complete VPN FRR functions. An end-to-end service convergence
fault recovery time independent of the size of private network routes. It is simple, reliable and
easy to deploy.
4.8 EVPN
ZXCTN 6120H-S supports EVPN(Ethernet Virtual Private Network). EVPN can be used to
create Ethernet VPN services.
EVPN is a VPN technology used for L2 network interconnection. The EVPN technology
adopts a mechanism similar to BGP/MPLS IP VPN. Through the extension BGP, an extended
and reachable information is used to transfer the MAC address learning and publishing
process between L2 networks at different sites from the data plane to control plane. Through
protocol extension, it can also support the creation of L3 VPN, thus the original independent
L2VPN and L3VPN can be unified into EVPN.
EVPN deployment can provide users with the following benefits:
 Reduce ARP broadcast traffic
 No needs for full links to save network resources
 Improve link utilization and transmission efficiency
4.9 SDN
SDN (Software Defined Network) decouples network functions and service processing
functions from network device hardware and controls abstracted network objects through an
external controller. SDN contains both controller and control protocol. The controller manages
and controls entire network devices, manages forwarding path delivery, controls network
devices and monitors their running statuses. Control protocol defines inter-operability
language between controller and network device. Controller performs forwarding path delivery
and device management monitoring on all network devices through control protocol.
ZXCTN 6120H-S supports SDN functionality through the Netconf interface and the YANG
model.

4.10 SR
4.10.1 Segment Routing MPLS
Segment Routing MPLS refers to Segment Routing based on MPLS forwarding plane,
hereafter referred to as Segment Routing. Segment Routing divides the network path into
segments and assigns segment IDs to these segments and the forwarding nodes in the
network. A forwarding path can be obtained by ordering the segments and network nodes in
order (Segment List).
SR functions supported by the ZXCTN 6120H-S have the following features:
 Supporting IS-IS extension SR
 Supports OSPF extension SR.
 Supports BGP extended SR.
 Supporting BGP-LS extended SR
 Supports PCEP extended SR.
 Supports SR BE
 Supports SR TE
 Supporting BFD for SR BE
 Supporting BFD for SR TE/SR TE LSP
 Supports SBFD for SR BE
 Supports SBFD for SR TE/TE LSP
 Supports TI-LFA
 Supports SR-Policy
4.10.2 SR Architecture
Transport network SR solution is based on SDN architecture and is implemented in

conjunction with a distributed control plane. SR identifies connection through an ordered set
of tags. The path of services varies with the contents of tag stack. This kind of flexible and
programmable feature seamlessly integrates with the SDN controller. SDN controller
calculates end-to-end SR paths and then generates a complete label stack and delivers it to

the device to create SR tunnel.
Figure 4- 4 SR mechanism
4.10.3 SR-BE
The distributed routing protocol based on SR extension implements basic network topology
collection, SR label forwarding table formation and FRR local protection. SR-BE (Segment
Routing Best Effort) means that IGP calculates the optimal SR LSP through the shortest path
algorithm. A tunnel using SR-BE can control the transmission path of packets in the network
according to the MPLS label of the first node.
4.10.4 SR-TE
SR is a segment routing technology. The information of the SR tunnel exists only with the
head node. Other nodes on the path are not aware of the service and cannot reserve
bandwidth for the service at the device layer, so the traffic engineering of the SR needs to be
completed by the controller. The controller maintains global topology and TE (Traffic
Engineering) information and calculates the end-to-end path according to the service request
(first node, last node and bandwidth) and routing policy (minimum hop number, minimum
latency, load balancing, etc.) to form a strict constraint path hop by hop and reserve
bandwidth on the control plane for end-to-end TE capability.
4.10.5 Segment Routing IPv6
Segment Routing IPv6 (Segment Routing IPv6) is a protocol designed to forward IPv6
packets over the network based on the concept of source routing. By inserting a route
extension header SRH (Segment Routing Header) in the IPv6 message, the SRv6 presses an
explicit IPv6 address stack in the SRH. The intermediate node continuously updates the
destination address and offsets the address stack to complete hop-by-hop forwarding. The

SRv6 does not use the MPLS technology and is compatible with the existing IPv6 network.
SRv6 has the following advantages:
 In the IGP domain, only needs to run IGP, while LDP/RSVP does not need to run,
simplifying the network.
 Does not need to maintain the status information of the forwarding path at intermediate
nodes, it solves the scalability problem of the large-capacity TE path and can implement
large-scale TE path planning. It can meet the massive connection requirements of 5G
networks.
 Only needs to calculate and maintain path information at the head node, it is more
suitable for SDN controller to calculate and deliver path information. Implements
automatic traffic engineering to achieve load balancing of network traffic.
 SR makes it possible for TI-LFA FRR.
 SRv6 can implement VPN more simply by directly using IPv6 address to identify VPN.
The SRv6 functions supported by ZXCTN 6120H-S have the following features:
 Supports IS-ISv6 extension SRv6
 Supports OSPFv3 extension SRv6
 Supporting BGPv6 extension SRv6
 Supports BGP-LS extension SRv6
 Supporting PCEP extension SRv6
 Supports SRv6
 Supports SRv6 TE
 Supports BFD for SRv6 BE
 BFD for SRv6 TE/SRv6 TE LSP
 Supports SBFD
 Supports SBFD for SRv6 TE/SRv6 TE LSP
 Supports TI-LFA
 Supports SRv6-Policy

4.11 Network Slicing
ZXCTN 6120H-S supports flexible Ethernet-based network slicing.
4.11.1 Network Slicing Architecture
Transport network slicing utilizes network topology resources such as links, nodes, ports, and
network elements of internal resources, virtualization and on-demand organization to form
multiple virtual networks vNet (i.e., slice networks). Overall structure is divided into customer
tenant layer, service layer, virtual network layer and physical network layer. Virtual network
(vNet) has the characteristics similar to a physical network, including separate management
plane, control plane, and forwarding plane. Each vNet can independently support a variety of
services such as EPL/EVPL, EPLAN/EVPLAN. Service is over vNet and the physical
network does not know the service which decouples physical network resources.
The vNet-based sub-slice supports operational services such as virtual operators,

sub-operators and network leases.
Figure 4- 5 Overview of Network slicing
4.11.2 Slicing based on FlexE
Flexible Ethernet (FlexE) is based on forwarding in PHY layer slice to provide tight pipeline
isolation and flexible bandwidth allocation. ZTE creatively introduces three key technologies:
slicing channel cross connection(SC-XC), OAM and protection. It successfully transforms
FlexE into a network-level technology, which is called slicing channel technology. Slicing
channel is network-level technology, which enable end-to-end channel isolation for different
services. Meanwhile, protection based on slicing channel can be switched within 1ms when
fault occurs.

4.12 Ultra-low Latency
Traditional packet device adopts a hop-by-hop forwarding policy for customer service packets.
Each node device in network needs to analyze the MAC layer and MPLS layer of the data
packet. This kind of solution would takes a lot of time and the single device forwarding latency
is up to dozens of us.
Slicing channel technology supports physical-layer forwarding based on the user service flow
through time-slot cross technology. User data packet does not need to be parsed on the P
node and the service flow forwarding process is almost real-time. The single-hop device
forwarding latency is less than 3us, laying a foundation for service extension.
Figure 4- 6 Slicing channel cross connection
4.13 Multicast Routing Protocol
ZXCTN 6120H-S supports intra-domain, inter-domain and client IPv4 and IPv6 multicast
routing protocols.
The main features of ZXCTN 6120H-S are as follows:
 Support IPv4 client multicast routing protocol, IGMPv1, IGMPv2 and IGMPv3.
 Support IPv6 client multicast routing protocol, MLDv1 and MLDv2.
 Support IPv4 multicast routing protocol, PIM-DM, PIM-SM and PIM-SSM.
 Support IPv6 multicast protocol, PIM-SMv6 and PIM-SSMv6.
 Support NG MVPN (a new generation framework for IP multicast data traffic passing

through BGP/MPLS VPN networks). NG MVPN (Next Generation MVPN) uses BGP to
transmit private network multicast protocol packages and private network multicast routes,
and builds MPLS P2MP tunnel-based multicast tunnels through BGP interactive messages. It
uses MPLS's mature label forwarding technology and tunnel protection technology to transmit
multicast traffic from the multicast source to the multicast user.
4.14 QoS Features
ZXCTN 6120H-S provides the perfect standards-based support for DiffServ, including traffic
classification, traffic policing, traffic shaping, congestion management, and queue scheduling.
By setting different QoS levels for accessed service flows, network operators can flexibly
provide differentiated services to their customers.
 Flow classification
ZXCTN 6120H-S supports the classification based on ports and L2/L3/L4 packet header
contents, including physical interface, source address, destination address, MAC address, IP
or application port numbers.
 Traffic policy
ZXCTN 6120H-S supports the traffic policing CAR function. It uses ACL to control service flow
access and allows CIR, CBS, EIR, and EBS based on flows to support dual-token buckets. If
traffic exceeds the contract rate, it will support policy actions such as discarding and color
tagging. And it supports ingress and egress traffic policing.
 Congestion avoidance and management
ZXCTN 6120H-S supports the following congestion avoidance and congestion management
functions:
 Support Weighted Random Early Detection (WRED) cache policy and setting of drop
upper/lower threshold and drop probability.
 Support Tail Drop cache policy
 Queue scheduling
ZXCTN 6120H-S adopts hybrid flexible queue scheduling according to different types of
services:
 Support service scheduling for 8 levels of queues per port.

 Support minimum/maximum bandwidth management per queue
 Support WRR, SP and SP+WRR hybrid scheduling.
 Traffic shaping
Traffic shaping limits the bursty traffic of network external connections so that information can
be transmitted at a smooth rate.
ZXCTN 6120H-S supports priority queue-based traffic shaping and port-based traffic shaping.
 Hierarchical QoS
ZXCTN 6120H-S can manage a large number of flexible hardware queues management, and
supports multi-layer H-QoS queue scheduling (5 layers), accurately matching the
high-precision requirements of users for multi-service and QOS management.
4.15 OAM Features
ZXCTN 6120H-S provides multi-level OAM mechanism and supports MPLS OAM, SR OAM,
Slicing Channel OAM, Ethernet OAM and link OAM for end-to-end service management, fault
detection and performance monitoring to ensure carrier-class QoS in packet transport
network.
The OAM standards and protocols supported by ZXCTN 6120H-S include IEEE 802.3ah,
IEEE 802.1ag, ITU-T Y.1731 and G-Ach+Y.1731.
4.15.1 Ethernet OAM
Ethernet OAM technology can effectively improve management and maintenance of Ethernet
and ensure the stable operation of the network. Link-level Ethernet OAM technology provides
link performance monitoring, fault detection, alarm, loop testing, etc. Network-level Ethernet
OAM technology detects link connectivity and identifies and locates a fault when it occurs.
 Support 802.3ah EFM
 Support 802.1ag CFM fault management and performance management
 Support Y.1731 fault management and performance management

4.15.1.1 Network-level Ethernet OAM
ZXCTN 6120H-S supports both IEEE 802.1ag and ITU-T Y.1731 protocols for fault
management and performance monitoring of Ethernet services, as shown in the table:
Table 4- 3 ZXCTN 6120H-S Ethernet OAM function
Function Description Protocol
CCM Continuity Check Message
RDI Remote Defect Indication

IEEE 802.1ag
LB Loop Back
LT Link Trace
ETH-CC ETH-Continuity Check
ETH-LB ETH-Loop Back
ETH-LT ETH-Link Trace
ETH-AIS ETH-Alarm Indication Signal
ETH-RDI ETH-Remote Defect Indication
ETH-LCK ETH-Locked ITU-T Y.1731
ETH-TST ETH-Test Signal function
Bidirectional LM Bidirectional Loss Measurement
Unidirectional LM Unidirectional Loss Measurement
Bidirectional DM Bidirectional Delay Measurement
Unidirectional DM Unidirectional Delay Measurement
4.15.1.2 Link-level Ethernet OAM
ZXCTN 6120H-S supports the 802.3ah-based Ethernet link layer OAM function to implement
loopback and link monitoring on the Ethernet access link.
Table 4- 4 ZXCTN 6120H-S Ethernet link OAM functions
Function Description Protocol
The local OAM entity discovers the remote OAM

OAM discovery entity and establishes a stable dialogue with it.
IEEE 802.3ah
Active and passive modes are supported.
OAM message delivery OAM packet transmitting and receiving

Monitor link events, send notification messages,

OAM link monitoring
and report to the NMS.
OAM remote loopback Loopback command sending and responding
OAM variable request MIB query Query request sending and responding
4.15.2 MPLS OAM
MPLS OAM technology provides a set of defect detection tools and defect correction
mechanisms for MPLS networks, which can effectively detect, identify and locate MPLS
user-level faults. When defection or fault occurs to a link or node, it quickly performs
protection switching, reducing the duration of failure and improving network reliability.
ZXCTN 6120H-S supports Ping/Trace and BFD. BFD (Bidirectional Forwarding Detection) is
a fault detection function with light load and short duration. It enables fault detection on any
type of channels between systems including direct connection to physical links, virtual circuits,
tunnels, and multi-hop routes.
4.15.3 SR OAM
SR OAM (Operations, Administration, and Maintenance) is mainly used to monitor the

connectivity of label switched paths (LSPs) and to quickly detect faults. SR OAM is currently
implemented mainly through Ping&Tracert including SR-BE Ping, SR-BE Tracert, SR-TE Ping
and SR-TE Tracert.
4.15.4 Slicing Channel OAM
Slicing channel OAM allows the operation and maintenance management of slicing channel
layer, effectively detects the faults of the slicing channel transmission layer, and quickly
performs protection switching when active channel is defective or faulty, ensuring
carrier-class QoS.
ZXCTN 6120H-S supports slicing channel OAM.
4.15.5 BFD
An important performance of network devices is the ability to quickly detect communication

faults between adjacent systems and create other paths as soon as possible. The main
function of BFD is to provide a low-load, fast fault detection mechanism between adjacent

forwarding engines. The combination of BFD and FRR technologies can implement
millisecond-level link detection and route switching functions on the forwarding plane.
The product supports the following main features of BFD:
 BFD for BGP detection
 BFD for OSPF detection
 BFD for IS-IS detection
 BFD for LDP detection
 BFD for TE detection
 BFD for static route detection
4.16 Telemetry
ZXCTN 6120H-S can report related data via telemetry technology.
As the equipment scale of the SDN increases, an increasing number of services are
transmitted and users have higher requirements for intelligent operation and maintenance of
the SDN, including higher-precision data monitoring for timely detection and rapid adjustment
of slight-burst traffic. Meanwhile, the monitoring process has little impact on the device's own
functions and performance to improve the utilization rate of devices and networks.
Telemetry is a remote technology for collecting data at high speed from physical or virtual
devices. The device periodically sends the device's interface traffic statistics, CPU, memory
data and other information to the collector in the push mode. Compared with the
question-and-answer interaction of traditional pull mode, it provides more real-time and
higher-speed data collection.
4.17 Protection Features
4.17.1 Device Level Protection
4.17.1.1 Power Board 1+1 Protection
ZXCTN 6120H-S is equipped with two -48V DC power inputs, they make hot-standby for each

other.
If one of them fails, the other one will continue to run properly.
4.17.2 Network Level Protection
ZXCTN 6120H-S offers a lot of network-level protection, including slicing channel protection,
SR protection, Tunnel/ PW protection, etc.
4.17.2.1 Slicing Channel Protection
Based on the standard FlexE interface technology, physical layer link group FlexE Group is
bound to multiple physical PHY layer links. If some PHY links fail, backup PHY links will be
used to transmit FlexE Client services, ensuring the normal delivery of services.
Protection at the slicing channel layer improves the reliability of customer services
transmission in the slicing channel. When customer services fail in a channel, they are quickly
switched to another channel for transmission. Protection method supports 1:1 slicing channel
protection.
4.17.2.2 SR Protection
SR technology can easily protect service paths. It is only required that the first node of the
service saves relevant protection path information.
 TI-LFA FRR
SR can provide TI-LFA FRR (Topology-Independent Loop-free Alternate FRR). TI-LFA FRR
provides link and node protection for SR tunnels. When a link or node fails, traffic will quickly
switch to the backup path and continue forwarding, maximally avoiding traffic loss.
 SR-TE Hot-Standby
Hot-Standby is to create active LSP and then backup LSP. The backup LSP is always in the
hot-standby status. The hot-standby LSP protects the entire LSP, which is an end-to-end
traffic protection measure.

4.17.2.3 Tunnel/PW 1:1 Protection
Tunnel 1:1 protection: The extended APS protocol is transmitted through the protection
channel to transfer the protocol status and switching status to each other. The devices at both
ends switches service according to the protocol status and switching status.
4.17.2.4 Ring Protection
Ring network protection can save fiber and related network resources and meet the strict
protection time requirements of transport network. Protection switching is completed within
50ms. ZXCTN 6120H-S supports wrapping ring and shared ring protection.
4.17.3 Access Link Protection
4.17.3.1 Ethernet LAG
Link Aggregation is to bind a group of physical Ethernet interfaces of the same rate as a
logical interface (link aggregation group) to increase bandwidth and provide link protection.
Ethernet LAG protection supports load balancing and non-load sharing of ports. In the load
balancing mode, the device automatically distributes the traffic load to multiple physical ports
in the aggregation group. When one of these physical ports fails, traffic on the failed port is
automatically shared with other physical ports. After the fault is recovered, traffic is
redistributed to ensure load balancing between the ports that are aggregated. In non-load
balancing mode, only traffic on the active link exists in the aggregation group and the standby
link is in the standby status. This actually provides a backup mechanism. When active link in
the aggregate fails, the system uses standby link as the active link to shield the link from
failure.
ZXCTN 6120H-S supports the following functions:
 UNI supports LAG and as well as manual aggregation and static LACP aggregation.
 UNI supports the active/standby mode (non-load sharing) in the LAG mode based on the
LACP.
 Support 200ms protection.

4.17.4 Other Protection Mode
ZXCTN 6120H-S provides high network availability for network using dynamic routing
protocols.
4.17.4.1 FRR
FRR can be used to create a backup path in advance. When a fault occurs, the router can
quickly switch services from the failed link to the backup path after detecting the link/node
failure, which reduces data loss. It supports the following functions:
 IP FRR
 LDP FRR
 TE FRR detour and bypass protection
 L3 VPN FRR
 L2 VPN FRR
4.18 SQM
4.18.1 RFC 2544/Y.1564
RFC 2544/Y.1564 provides a benchmark for network device testing. It specifies a set of
testing procedures and methods so that service providers and users agree on test
implementation and results under the same benchmark.
ZXCTN 6120H-S supports throughput, packet loss, latency and jitter testing.
4.18.2 TWAMP
TWAMP protocol is a standards-based, very efficient performance monitoring protocol that

extends from the One-Way Active Measurement Protocol (OWAMP) specified in RFC 4656
and includes TWAMP Control and TWAMP Test Protocol. TWAMP Control Protocol is used to
initialize, start and stop the test process, while the TWAMP Test Protocol is responsible for
exchanging test messages between two TWAMP test entities.
 Support Full and Light modes.

 Support packet loss rate, delay and jitter testing.
4.19 Synchronization Feature
As packet transport platform with the network-level synchronization function, ZXCTN

6120H-S supports multiple ways to select synchronous clock source as the system clock and
assign timing to other devices in the network, enabling clock synchronization and time
synchronization of the network.
ZXCTN 6120H-S supports the following synchronization functions:
 Provide external clocks such as BITS and 1PPS+TOD, and external time synchronization
interfaces.
 Support synchronous Ethernet clocks on the physical layer, which meets the
requirements of G8275.1.
 Support IEEE 1588v2 protocol for clock and time synchronization.
 Support SSM information transfer and BMC algorithm for all-network clock
synchronization. It automatically select high-priority clocks and prevents timing loop, ensuring
reliable transmission of synchronization.
ZTE is the first vendor in the industry to propose a unique "Synchronous Ethernet +1588" time
transfer solution, which provides 1588V2 time synchronization based on synchronous
Ethernet. Hardware can inserts and extracts accurate time stamps according to the 1588
protocol, effectively improving time synchronization accuracy.
 Comply with higher requirements of 5G services for time synchronization and support
high-precision time synchronization.
ZTE devices use higher-precision clock sources, more advanced clock synchronization
algorithms and high-precision time stamps are inserted and extracted at the hardware level to
support ultra-high-precision master/slave clock synchronization solution, meeting the
requirements of 5G services for time synchronization.

4.20 Safety Features
4.20.1 AAA ID Authentication
ZXCTN 6120H-S supports the AAA (Authentication, Authorization, Accounting ) mechanism

and uses command line hierarchical protection mechanism for user logging together with
authentication and authorization modes and identifies network management users on NM.
The AAA-based ZXCTN 6120H-S can prevents unauthorized users from logging in.
Devices provide different AAA functions for different user authentication policies. The access
authentication policy varies with access authentication requirements to provide different
authentication and authorization for different users.
AAA mechanism supports three types of user authentication:
 Local account authentication
 RADIUS (Remote Authentication Dial In User Service) authentication
 TACACS+ (Terminal Access Controller Access Control System) Authentication
AAA mechanism supports four types of authorization:
 Direct trust authorization: Directly authorized due to user trust without an account.
 Local account authorization: Authorized according to the local user account.
 TACACS+ authorization: TACACS+ detachable authentication & authorization. The

TACACS+ server authorizes the user.
 Authorization after successful RADIUS authentication: RADIUS protocol authentication &

authorization cannot be split.
4.20.1.1 Command Line Hierarchical Protection
ZXCTN 6120H-S allows users to log in telnet via Ethernet interfaces. However, for security
reasons, devices require users to perform login authentication. Only the user who completes
authentication can log in, configure and maintain.
ZXCTN 6120H-S provides hierarchical protection for operation and maintenance command
lines. The command line has 4 levels: access, supervision, configuration and management
and users login also have four levels. After logging in to ZXCTN 6120H-S, users can only

operate the command line equal to or lower than their own level.
4.20.1.2 Protocol Security Authentication
ZXCTN 6120H-S provides different protocol security authentication functions for SSH, routing
protocols and SNMP.
 SSH protocol security authentication
 Support MD5 authentication.
 Support SHA1 authentication.
 Routing protocol security authentication
 OSPF supports information authentication.
 OSPF supports MD5-based authentication.
 SNMP security authentication
 Support SNMPv3 encryption and authentication
4.20.2 Network Security
4.20.2.1 VPN Isolation
ZXCTN 6120H-S uses an isolated interface such as VLAN and extension technologies (such
as PVLAN and QinQ) to shield user network on the transport network, ensuring the security of
users service network and controlling unnecessary broadcasts to increase network
throughput.
IP VPN based on IP/MPLS can isolate services well with good QoS, scalability and
manageability.
4.20.2.2 Ethernet VLAN/MAC Spoofing and Attack
ZXCTN 6120H-S uses VLAN plus MAC to filter illegal information so as to improve network
security. Administrators add static entries to MAC address table and bind specific MAC
addresses to the interface to prevent attacks based on MAC address spoofing.
ZXCTN 6120H-S can filter illegal MACs. When the maintenance staff knows that these MAC

address information have the possibility of attack, they will be manually configured as an
illegal MAC address. When device receives a message, it compares the source or destination
MAC address of the message with the MAC address entry. If this MAC is illegal in the MAC
table, these information will be discarded and the source will not be notified.
In addition, ZXCTN 6120H-S applies ACLs to ports. By analyzing VLAN, IP address, port
number and protocol number of the information, devices can automatically filter information to
prevent network attacks.
4.20.2.3 Prevention of Other Attacks
ZXCTN 6120H-S also supports the following checks and anti-attack features:
 Source address spoofing
 LAND
 SYN Flood (TCP SYN)
 Smurf
 Ping Flood (ICMP Echo)
 Teardrop
 Ping of Death
5 Technical Indexes and Specifications
5.1 Interface Indexes
Table 5- 1 GE optical interface performance indexes
Item Performance index
Nominal rate 1000Mbit/s
1000BASE-SX 1000BASE-LX 1000BASE-LX 1000BASE-ZX

Optical interface type
(0.5km) (10km) (40km) (80km)
Connector type LC LC LC LC
Fiber type Multi-mode Single-mode Single-mode Single-mode
Central wavelength (nm) 850 1310 1310 1550

Mean Launched Power

-9.5~-4 -9~-3 -4~5 0~5
(dBm)
Receiving sensitivity
<=-17 <=-20 <=-22 <=-22
(dBm)
Table 5- 2 10GE optical interface performance indexes
Nominal rate 10000Mbit/s
10GBASE-SR 10GBASE-LR 10GBASE-ER 10GBASE-ZR

Optical interface type
(0.3km) (10km) (40km) (80km)
Connector type LC LC LC LC
Fiber type Multi-mode Single-mode Single-mode Single-mode
Central wavelength (nm) 850 1310 1550 1550
Mean Launched Power

-7.3~-1 -8.2~0.5 -4.7~4 0~4
(dBm)
Receiving sensitivity (dBm) <=-11.1 <=-10.3 <=-14.1 <=-24
Nominal rate 25,000Mbit/s
Optical interface type 25GBASE-SR (0.1km) 25GBASE-LR (10km) 25GBASE-ER (40km)
Connector type LC LC LC
Fiber type Multi-mode Single-mode Single-mode
Central wavelength (nm) NA 1310 1310
Mean Launched Power

NA -4.5~+2.5 -3.0~+6
(dBm)
NA <=-9.6 <-19.5
(dBm)

Optical interface type 50GBASE-SR (0.1km) 50GBASE-LR (10km) 50GBASE-ER (40km)
Central wavelength (nm) NA 1304.5-1317.5 1304.5-1317.5
Mean Launched Power

NA -4~+4.2 +1.5~+8.0
(dBm)
NA <=-8.8 <=-15.1
(dBm)
100GBASE-SR4
Optical interface type 100GBASE-LR4(10km) 100GBASE-ER4(40km)
(0.1km)
1295.56/1300.05/1304.5 1295.56/1300.05/1304.58/130
Central wavelength (nm) NA
8/1309.14 9.14
Mean Launched Power

NA -2.5~+2.9 -2.7~+2.9
(dBm)
NA <=-10.3 <=-21.4
(dBm)

6 Networking Application
Figure 6- 1 ZXCTN 6120H-S application scenario
ZXCTN 6120H-S is positioned as a new generation product in network access layer, which
can meet various application scenarios such as enterprise customer services, family
customer services, and mainly 4G/5G mobile backhaul services.
7 Operation and Maintenance

ZXCTN 6120H-S uses ZENIC ONE to manage and monitor all NEs in a unified manner .
ZENIC ONE R22 system integrates SDN control and network management functions. SDN
control provides path computing, network optimization, and 5G slice deployment. Network
management is based on the FCAPS (Fault, Configuration, Accounting, Performance and
Security) universal management function proposed by ITU-T TMN. It provides complete fault
management, configuration management, accounting support, performance management,
and security management. The accounting management part provides the basic data support,
and the main accounting functions are provided by the OSS/BSS management system on the
operator side.
8 Environmental Indexes
8.1 Storage
Climate environment
The climate requirements for equipment storage are described below.

Table 8- 1 Climate requirements for equipment storage
Item Index
Altitude <=4000 m
Air pressure 62kPa ~ 106kPa
Temperature -40°C ~ +70°C
Temperature variance ratio <=1°C/min
Relative humidity 5% ~ 100%
Solar radiation <=1120 W/s2
Heat radiation <=600 W/s2
Wind speed <=20m/s
Water-proof Requirements
Storage requirements for on-site devices: keep the devices indoor.
Ensure that there is no water on the storage room floor, so that the water will not leak on the
packing container of the equipment. Furthermore, the storage position should be far away
from the leaking places of the firefighting equipment and heating system.
If the equipment has to be stored outside, the requirements are listed as follows:
 Ensure that the packing of the equipment is in good condition without any damages.
 Rainwater-proof measures should be taken, so that the rainwater cannot damage the
pack of the equipment.
 Ensure that no water in the storage place, so that the packing container of the equipment
will not be leaked.
 Keep the packing container out of direct sunlight.
Biological environment
 Avoid the proliferation of microorganisms such as fungi and mold.
 Prevent the presence of rodents (such as mice).
Air cleanliness
 No explosive, conductive, magnetically conductive and corrosive dust.
 The concentration of mechanically active substances meets the requirements of Table

8-2.

 The concentration of chemically active substances meets the requirements of Table 8-3.
Table 8- 2 Concentration requirements for mechanically active substances
Mechanically active substance Content
Suspended dust <=5.00 mg/m3
Dust fall <=20.0 mg/m2·h
Gravel <=300 mg/m3
Table 8- 3 Concentration requirements for chemically active substances
Chemically active substance Content
Sulfur dioxide SO2 <=0.30 mg/m3
Hydrogen sulfide H2S <=0.10 mg/m3
Nitrogen dioxide NO2 <=0.50 mg/m3
Ammonia NH3 <=1.00 mg/m3
Chlorine gas Cl2 <=0.10 mg/m3
Hydrochloric acid HCl <=0.10 mg/m3
Hydrofluoric acid HF <=0.01 mg/m3
Ozone O3 <=0.05 mg/m3
8.2 Transportation
Climate Environment
The climate requirements for equipment transportation are described below.
Table 8- 4 Requirements for climate
Item Index
Altitude <=4000 m
Air pressure 62 kPa ~ 106kPa
Temperature -40°C ~ +70°C
Temperature variance ratio <=1°C/min
Relative humidity 5% ~ 100%

Item Index
Wind speed <=20 m/s
Water-proof Requirement
Storage requirements for on-site devices: keep the devices indoor.
Ensure that there is no water on the storage room floor, so that the water will not leak on the
packing container of the equipment. Furthermore, the storage position should be far away
from the leaking places of the firefighting equipment and heating system.
If the equipment has to be stored outside, the requirements are listed as follows:
 Ensure that the packing of the equipment is in good condition without any damages.
 Rainwater-proof measures should be taken, so that the rainwater cannot damage the
pack of the equipment.
 No water in the transportation vehicle.
Air cleanliness

8-5.
 The concentration of chemically active substances meets the requirements of Table 8-6.
Gravel <=100 mg/m3

8.3 Operation
Environment temperature and relative humidity requirements and other climate environment
requirements for equipment operation are described in the following table:
Table 8- 7 Requirements for temperature and humidity
Item Specifications
-40°C ~ +65°C ( 50GE/100GE only support

Environment temperature
-5°C ~ +55°C)
Relative humidity 5%~95%

Note: Temperature and humidity are measured 1. 5m above the floor and 0. 4m in front of the equipment. Short term running means
that the equipment works continuously for no more than 96 hours and works for no more than 15 days in one year.
Table 8- 8 Other climate environment requirements
Item Index
Altitude <=4000 m
Air pressure 62 kPa ~ 106kPa
Temperature variance ratio <=30°C/h
Wind speed <=5 m /s

Air cleanliness

8-9.
 The concentration of chemically active substances meets the requirements of Table

8-10.
Dust particles <=3x105 particles/m3
Suspended dust <=5.00 mg/m3
Gravel <=300 mg/m3
Nitrogen oxides NOx <=0.50 mg/m3

9 Abbreviation
Abbreviation Full name
ACL Access Control List
AG Access Gateway
APC Automatic Power Control
APS Automatic Protect Switch
ASIC Application Specific Integrated Circuit
ARPU Average Revenue Per User
ATCA Advanced Telecom Computing Architecture
BFD Bidirectional Forwarding Detection
BGP Border Gateway Protocol
CAC Connection Access Control
CAM Content-addressable Memory
CAN Controller-area Network
CAPEX Capital Expenditures
CDN Content Distribution Network
CDR Call Detail Record
CE Carrier Ethernet
CESoPSN Circuit Emulation Services over PSN
CMS Center Media Server
CV Connectivity Verification
DoS Denial of Service
DPI Deep Packet Inspection
EAPS Ethernet Automatic Protection Switching
ECMP Equal Cost of Multi-path
E-LAN Ethernet LAN
E-LINE Ethernet LINE
EMS Edge Media Server
ESRP Ethernet standby Routing Protocol Ethernet
E-TREE Ethernet TREE

FDDI Fiber Distributed Digital Interface
FFD Fast Failure Detection
FR Frame-relay Protocol
FRR Fast Reroute
GFP General Format Protocol
GPS Global Position System
HDLC High Level Data Link Control
H-VPLS Hierarchical Virtual Private Lan Service
IAD Integrated Access Device
ICMP Internet Control Message Protocol
IGMP Internet Group Management Protocol
IMA Inverse Multiplexing for ATM
IPMS Intelligent Platform Message sub-system
IPMC Intelligent Platform Message control
IPOE IP over Ethernet
IPS Intrusion Detection Systems
IPMB Intelligent Platform Message Bus
ISIS Intermediate System-Intermediate System
LACP Link Aggregation Control Protocol
LIC Line Interface Card
LPC Line Process Card
LSP Label Switch Path
MCE Multi-Instance Customer Edge
MPLS Multi-Protocol Label Switching
MSG Media Service Gateway
MSTP Multiple Spanning Tree Protocol
MTU Maximum Transmission Unit
MVR Multicast VLAN Registration
NE Network Element
NGN Next Generation Network
OAM Operations Administration and Maintenance

OPEX Operation Expense
OSPF Open Shortest Path First
PIM Protocol Independent Multicast
PIM-DM Protocol Independent Multicast-Dense Mode
PIM-SM Protocol Independent Multicast-Sparse Mode
PIM-SSM Protocol Independent Multicast-Source Specific Multicast
PMD Physical Medium Dependent physical
PRV Preview
PSN Packet Switch Network
PUPSPV Per User Per Service Per VLAN
PVLAN Private VLAN
PW Pseudo-wire
PWE3 PW Emulation End to End
RED Random Early Detection
RIP Routing Information Protocol
RNC Radio Network Controller
ROS Routing Operation System
RP Rendezvous Point
RPR Resilient Packet Ring
RSTP Rapid Spanning Tree Protocol
SAToP Structure-Agnostic TDM over PSN
SDH Synchronous Digital Hierarchy
SLA Service Level Agreement
SMS Service Management System
SNMP Simple Network Management Protocol
SSM Source Specific Multicast
STP Spanning Tree Protocol
SynE Synchronization Ethernet
SVLAN Select VLAN
TCO Total Cost of Ownership
TCP Transport Control Protocol

TDM Time Division Multiplex and Multiplexer
TL1 Transaction Language 1
TM Traffic Manager
UDP User Datagram Protocol
URPF Unicast Reverse Path Forwarding
VLL Virtual Leased Line
VOIP Voice over IP
VPLS Virtual Private LAN Service
VPN Virtual Private Network
VPWS Virtual Private Wire Service
VRF Virtual Routing and Forwarding
WRED Weighted Random Early Detection
WFQ Weighted Fair Queuing
ZESR ZTE Ethernet Smart Ring
ZESS ZTE Ethernet Smart Switching
ZGMP ZTE Group Management Protocol
ZGMS ZTE General Multicast System
ZTP ZTE Topology Discovery Protocol

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ZXCTN 6120H-S V5.10.

ZXCTN 6120H-S V5.10.00Product Description

V1.0 2021/05/30 ZTE ZTE The first draft

© 2022 ZTE Corporation. All rights reserved.

ZTE Confidential & Proprietary 3

3.1 Equipment Switching Capability............................................................................................... 10

3.2 Interface Type and Quantity...................................................................................................... 10

3.3 Physical Performance.................................................................................................................11

3.4 System Architecture....................................................................................................................12

3.4.1 System Hardware Architecture...................................................................................13

3.4.2 System Software Architecture.................................................................................... 15

3.4.3 Control System Architecture....................................................................................... 15

4 Functions and Features......................................................................................................................16

4.1 Multiservice Transport Capability............................................................................................. 16

4.1.1 Ethernet Service............................................................................................................16

4.2 FlexE Functions...........................................................................................................................17

4.3.1 Ethernet Basic Functions.............................................................................................18

4.3.2 VLAN and VLAN Extension Features........................................................................18

4.3.3 Link Aggregation (LAG)............................................................................................... 19

4.3.4 STP Functions............................................................................................................... 19

4.3.5 DHCP Relay...................................................................................................................20

4.4.1 L3 Basic Functions....................................................................................................... 20

4.4.2 L3 Routing Protocols.................................................................................................... 22

4.4.3 IPv6 Related Functions................................................................................................22

4 ZTE Confidential & Proprietary

4.5.1 Overview of MPLS........................................................................................................ 22

4.5.2 MPLS Network Architecture........................................................................................ 23

4.5.3 MPLS Basic Functions................................................................................................. 23

4.6 MPLS L2 VPN..............................................................................................................................25

4.7 BGP/MPLS L3 VPN.................................................................................................................... 26

4.10.1 Segment Routing MPLS............................................................................................ 28

4.10.5 Segment Routing IPv6...............................................................................................29

4.11 Network Slicing..........................................................................................................................31

4.11.1 Network Slicing Architecture.....................................................................................31

4.11.2 Slicing based on FlexE.............................................................................................. 31

4.12 Ultra-low Latency...................................................................................................................... 32

4.13 Multicast Routing Protocol.......................................................................................................32

4.14 QoS Features............................................................................................................................ 33

4.15 OAM Features........................................................................................................................... 34

4.15.1 Ethernet OAM..............................................................................................................34

4.15.2 MPLS OAM.................................................................................................................. 36

4.15.4 Slicing Channel OAM................................................................................................. 36

4.17 Protection Features.................................................................................................................. 37

4.17.1 Device Level Protection.............................................................................................37

ZTE Confidential & Proprietary 5

4.17.2 Network Level Protection.......................................................................................... 38

4.17.3 Access Link Protection.............................................................................................. 39

4.17.4 Other Protection Mode...............................................................................................40

4.18.1 RFC 2544/Y.1564....................................................................................................... 40

4.19 Synchronization Feature..........................................................................................................41

4.20 Safety Features......................................................................................................................... 42

4.20.1 AAA ID Authentication............................................................................................... 42

4.20.2 Network Security.........................................................................................................43

5 Technical Indexes and Specifications............................................................................................44

5.1 Interface Indexes.........................................................................................................................44

7 Operation and Maintenance.............................................................................................................. 47

6 ZTE Confidential & Proprietary

Figure 3- 2 ZXCTN 6120H-S Sub-rack structure..................................................................................13

Figure 3- 3 ZXCTN 6120H-S slot distribution ......................................................................................14