PTN Protection Subject V1.0. Contents PTN Protection Type PTN Protection Principle and Application PTN Protection Summary

PTN Protection Subject

V1.0

Contents

PTN Protection Type PTN Protection Principle and Application PTN Protection Summary

PTN Protection Classification

Note: The network-level protection here can be nested to meet more complicated networking protection demands.

PTN Protection

Network-Level Protection

Card-Level Protection

Port-Level Protection

Linear

protection

Sub

net protection

Ring netw

ork

protection

PW

dual-hom

ing

protection

LAG

protection

IMA

protection

TP

S protection

Card 1+

1 protection

Contents


PTN Protection Principle and Application

Card-Level Protection Card 1+1 protection TPS protection

Port-Level Protection LAG protection IMA protection

Network-Level Protection Linear protection Subnet protection Ring network protection PW dual-homing protection


Card protection application

Redundant unit

Core nodeConvergence

nodeAccess node

Switching n+1/1+1 1+1 N/A or 1+1

Main control 1+1 1+1 N/A or 1+1

Clock 1+1 1+1 N/A or 1+1

Power 1+1 1+1 N/A or 1+1

Fan 1+1 1+1 N/A or 1+1


Card protection description Currently, the main control of 6200/6300/9000 is in a

1+1 protection mode. The power of 6000 is in a 1+1 protection mode. The AC power of 9000 is in a 2+1 protection mode.

The DC power is in a 1+1 protection mode. The TPS on 6300 is in a 1:2 protection mode which is

achieved on Slot1 and Slot2. Two cards inserted in the slots are E1 interface cards. In the low-speed slot is the E1 processign card whose protection will be provided in 6300 version 2.0.





Port-Level Protection - LAG Protection

LAG Protection ScenarioApplication

ScenarioProtection type

PTN and RNCLAG protection (Active/standby/load sharing)

PTN and SR/Switch LAG protection (load sharing)

Interconnection between PTN and MSTP

MSP protection/LAG protection GE/FE ： LAG protectionSTM-1: MSP protection

RNC

Access layer

GEProtection path

Work path

MSTP

ADMADM

GE/FE ： LAG protectionSTM-1: MSP protection

Convergence layer

10GE

core layer

10GE

SR

LAG protection

LAG protection

The LAG port protection provides the port

redundancy protection of the Ethernet

service between the PE node of the PTN and

the service node. This protection mode is

commonly used for the user side port.

Port-Level Protection - LAG Protection

Mode1: Active/standby mode; when the active/standby LAG mode is adopted, traffic is transmitted only on one port, namely on the active port rather than the standby port.

Mode1: Active/standby mode; when the active/standby LAG mode is adopted, traffic is transmitted only on one port, namely on the active port rather than the standby port.

Mode2: Load sharing mode; in this case, traffic is uniformly allocated on two ports for transmission.The way of distinguishing the traffic can be based on the destination IP address or the destination MAC address, and the source MAC address. The load sharing mode can support 2 - 16 ports. Currently, the load sharing mode is commonly used for protection on the UNI port.

Mode2: Load sharing mode; in this case, traffic is uniformly allocated on two ports for transmission.The way of distinguishing the traffic can be based on the destination IP address or the destination MAC address, and the source MAC address. The load sharing mode can support 2 - 16 ports. Currently, the load sharing mode is commonly used for protection on the UNI port.

Wave divisionWave division

Port-Level LAG Protection Switchover Principle

The LAG protection can be divided into two modes: Static and Dynamic.

In the static mode you need to manually assigns the physical ports to be aggregated. The dynamic mode is based on the IEEE802.3ad protocol, determining ports to be aggregated according to the protocol.

Generally, we use the static mode.

Port-Level LAG Protection Switchover Principle When shall we configure the static or dynamic

mode? Depends on the mode supported by the opposite end. If the opposite end is configured as the static mode,

the ZTE equipment must also be configured as the static mode.

If the opposite end is configured as the dynamic mode, the ZTE equipment must also be configured as the dynamic mode.

Port-Level Protection - IMA Protection

What is IMA? Inverse Multiplexing for ATM Based on cells, the ATM cell stream is inversely

multiplexed to multiple low-speed links for transmission; then on the remote end, the cell streams of multiple low-speed links are joined to restore the ATM cell stream same as the orignal one.


What characteristics of the IMA technology are? IMA can multiplex multiple low-speed links, achieving

the transmission of the ATM cell stream on the high-speed broard, and improving the link efficiency and transmission reliability through the statistical multiplexing.


What is IMA protection? The IMA protection means: If a link in an IMA group is

invalid, the cells will be shared by other normal links for transmission, thus to achieve the service protecion.

Port-Level Protection - IMA Protection IMA Transmission Diagram

The IMA group ends at the end of each IMA virtual connection. In the sending direction, the cell stream received from the ATM layer, based on cells, is distributed to multiple physical links in the IMA group. However, at the receiving end, the cells received from different physical links, based on cells, are re-joined to a cell stream same as the original cell stream.

ATM cell streamATM cell stream ATM cell streamATM cell stream

IMA virtual linkIMA virtual link

Node ANode A Node ZNode Z

IMA groupIMA groupIMA groupIMA group

E1 interfaceE1 interface










Network-Level Protection: 1+1/1:1 Linear Protection

Switchover principle: The PE node detects the TMP-layer OAM packet and sends the OAM detection frame every 3.3ms. If

the remote CC packet fails to be received in 3.5 cycles at the local end, the tunnel protection switchover is triggered.

The switchover point and the bridge point are both PE node.

In 1:1 single-send-single-receive mode, the APS protocol is applied for bi-directional switchover, supporting any service

types; commonly used in current network

In 1+1 dual-send-dual-receive mode, the selective receiving port is the default work port. Both the local port and the remote

port support the uni-directional switchover and the P2P services.

Switch

over

node

BTS/NodeB

Residential

Business

E-NB

BRAS

SR

BSC/RNC

aGW

Work pathWork path

Protection pathProtection path

Switch

over

node

Network-Level Protection: 1+1/1:1 SNC Subnet Protection

Most of the characteristics are the same as those of the linear protection.

The difference is that the switchover point and the bridge point can be P node or PE node.

Commonly used in interconnection with other manufacturers' equipment and only protects ZTE equipment.

Also applied in a rign-chain networking mode; configures subnet protection at the connection point of the ring-chain

network.

Switch

over

node

BTS/NodeB

Residential

Business

E-NB

BRAS

SR

BSC/RNC

aGW

Work pathWork path

Protection pathProtection path

Switch

over

node

Linear and Subnet Protection Switchover Principle

Prerequisite: Continuously sending CC packet detection should be ensured and the tunnel connectivity should be protected.

If the 1+1 protection of the APS protocol is not enabled, the APS packets between switchover nodes are not transmitted, namely, the remote end does not trigger the switchover at the local end through the APS packet.The local end performs switchover only on the receiving port. The switchover is performed based on the received alarms and the related commands.

If the 1+1 protection of the APS protocol is not enabled, the APS packets between switchover nodes are not transmitted, namely, the remote end does not trigger the switchover at the local end through the APS packet.The local end performs switchover only on the receiving port. The switchover is performed based on the received alarms and the related commands.

Switchover priority of linear protection:LP (Lock Protection) >SF-P (Signal Failure-Protection)>FS (Force Switchover)>SF (Signal Failure) >SD (Signal Deterioration) >MS (Manual Switchover)Note: The above situation describes that when the signalof the protection channel fails, and the protection lock command is not executed previously, the system may trigger the selective receiving channel to switch over to the work channel.

Switchover priority of linear protection:LP (Lock Protection) >SF-P (Signal Failure-Protection)>FS (Force Switchover)>SF (Signal Failure) >SD (Signal Deterioration) >MS (Manual Switchover)Note: The above situation describes that when the signalof the protection channel fails, and the protection lock command is not executed previously, the system may trigger the selective receiving channel to switch over to the work channel.

When the 1:1 protection of the APS protocol is enabled, The APS packets are to be transmitted between the service switchover nodes, advising the opposite party of its own switchover status.Switchover is divided as Locally Triggered Switchover, and Remotely Triggered Switchover.The switchover basis and the priorities are the same as those in 1+1 protection mode.

When the 1:1 protection of the APS protocol is enabled, The APS packets are to be transmitted between the service switchover nodes, advising the opposite party of its own switchover status.Switchover is divided as Locally Triggered Switchover, and Remotely Triggered Switchover.The switchover basis and the priorities are the same as those in 1+1 protection mode.

Linear APS Packet Details

Type (Hex) Name01 CV 02 FDI 20 LBR21 LBM23 LCK25 TST27 APS28 SCC29 MCC

LMR2B LMM2D 1DM2E DMR

DMM30 EXR31 EXM32 VSR33 VSM35 SSM37 CSF

Byte segment format of the linear APS informationByte segment format of the linear APS information

Linear APS Packet DetailsFirst byte b1 - b4 request/state

1111LP

1110SF-P

1101FS

1100SF

1010SD

1000MS

0110WTR

0100EXER

0010RR

0001DNR

0000NR

Others Reserved

First byte b1 - b4 request/state1111

LP1110

SF-P1101

FS1100

SF1010

SD1000

MS0110

WTR0100

EXER0010

RR0001

DNR0000

NR

Others Reserved

First byte: b5 - b8 Protection typeb5 0 indicates no APS channel; 1 indicates the

APS channelb6 0 indicates 1+1 protection; 1 indicates 1:1

protectionb7 0 indicates uni-directional protection; 1

indicates bi-directional protectionb8 0 indicates no return; 1 indicates return

Second and third byte b1 - b8 indicate request signal and bridge signal respectively0 indicates no signal1-254 indicates normal service255 indicates no protection signal

Fourth byte b1 - b8 reserved

First byte: b5 - b8 Protection typeb5 0 indicates no APS channel; 1 indicates the

APS channelb6 0 indicates 1+1 protection; 1 indicates 1:1

protectionb7 0 indicates uni-directional protection; 1

indicates bi-directional protectionb8 0 indicates no return; 1 indicates return

Second and third byte b1 - b8 indicate request signal and bridge signal respectively0 indicates no signal1-254 indicates normal service255 indicates no protection signal

Fourth byte b1 - b8 reserved

OAM service flow (TMP) of LSP1:1

OAM service flow (TMP) of LSP1:1

OAM service flow (TMS)of ring network protection

OAM service flow (TMS)of ring network protection

Work tunnel: TMP1

Protection tunnel: TMP2

Protection route: ----

NE1

NE5NE6

NE2 NE3

NE4

NE1

NE5NE6

NE2 NE3

NE4

Switchover node

Switchover node

The node where failure is detected sends a request through APS to the adjacent node. When a node detects failure or receives an APS request from other nodes, the service sent to the failed Span is switched over to a reverse direction (away from the defect). The service reaches another switchover node along the longer path, and then re-switched over to the work direction.

Network-Level Protection: Ring Network Protection

Ring Network Protection Switchover Principle Switchover principle analysis: The OAM packet of TMS is

detected. The switchover node is the connection point where failures occur. To switch over the faulty point is to switch over the service tunnel to the ring protection tunnel.

Ring Netwok protection needs to allocate an APS-ID to each node. Similar to the multiplexed segment protection in SDH, the sent APS packet contents include the faulty point, launching point, the detailed switchover request, and the switchover status at this point.

OAM saves costs and bandwidth. The device load is less heavy. When LSP>=1000, OAM adopts the LSP1+1 protection mode. The total bandwidth of OAM is 1000*0.2=200M. If OAM adopts the ring network protection mode, the OAM bandwidth is 1*0.2=0.2M.

Ring Network Protection Switchover Principle

Prerequisite for ring network protection

Prerequisite for ring network protection

A fault detection system should exist between every two nodes on

the ring.

A fault detection system should exist between every two nodes on

the ring.

The node on the ring responds to the fault timely, advising the opposite end of the fault.

The node on the ring responds to the fault timely, advising the opposite end of the fault.

Correponding methods for achievement

Correponding methods for achievement

Enable the CC detection function Enable the CC detection function

Each station on the ring is alloted with an APS ID, considering the fault originating node and the destination adjacent node when connecting the APS packets. The destination node responds to the request and performs the switchover.

Each station on the ring is alloted with an APS ID, considering the fault originating node and the destination adjacent node when connecting the APS packets. The destination node responds to the request and performs the switchover.

1. TMPLS OAM performs protection on the neighbors on the ring network.2. When TMPLS OAM finds a failure between neighbors, it advises the APS module on this node to send the APS

switchover packets simultaneously in two directions of the ring. 3. When the node on the ring receives the APS switchover packets and finds that the destination node is not itself, it

forwards the packets directly to its neighbor; When the node finds that the destination node is itself, and that the source node is its neighboring node, it knows that the link between itself and the source node is down. Therefore, the APS module advises the TMPLS OAM module to perform switchover.

4. In some special case that the singal on some middle node fails, switchover is performed on both ends of the disconnected services according to SF.

Ring Protection Packet DescriptionByte segment format of the ring APS information：Byte segment format of the ring APS information：

Byte segment format of the ring APS informationByte segment format of the ring APS information

Request codes of ring protection Bridge Request

Request codes of ring protection Bridge Request

Switchover priorities of ring network protection: LP>FS>SF>MS

Network-Level Protection: PW Dual-Homing Protection

Dual-homing protection is a protection

mechanism that combines the LSP 1:1/1+1 path

protection and PW protection.

Description for nesting protection mode:The work PW is borne on a tunnel protection group (to protect the internal network fault); The protection PW is borne on a tunnel.

:Work tunnel of the work PW

:Protection tunnel of the work PW

:Bearer tunnel of the protection PW

10 GE convergence

ring

GE

access

ring

RNC

Protection tunnel pathWork tunnel path

Protection PW

Broken fiber1

Broken fiber2

Broken fiber1: belongs to an internal failure of the PTN network; TMP-LOC triggers the tunnel switchover.

Broken fiber2: belongs to a failure between PTN and the service-side network layer; TMC-CSF triggers the PW switchover.

Broken fiber2: belongs to a failure between PTN and the service-side network layer; TMC-CSF triggers the PW switchover.

Note: At this moment, if RNC adopts the active/standby mode, the ZTE equipment PW chooses the 1:1 configuration mode.If RNC adopts the load sharing mode, the ZTE equipment PW chooses the dual-receive-singel-send mode.

Specific Descriptions for PW Dual-Homing Protection Switchover

Key knowledge points on PW dual-homing protection

Key knowledge point 1:For the case that RNC adopts the LAG active/standby mode:The active PW and the tunnel protection should exist at the same time to prevent the broken fiber inside the PTN network, however, at this moment, RNC does not perform switchover. The internal PTN network still can switch the service over to the active receiving node, ensuring that the service is not interrupted.Key knowledge point 2:For the case that RNC adopts the LAG load-sharing mode: The node that selectively receives PW adopts the dual-receive-single-send mode. For a base station, the LAG load sharing of RNC is branched out based on the BS IP addresses. Therefore, the node also adopts the singel-receive mode for a BS service stream. In this case, do not adopt the tunnel protection.Key knowledge point 3:The PW dual-homing protection switchover does not depends on APS for switchover other than the LOC and CSF switchover on the local end. The difference between 1:1 and 1+1 only lies in single receiving or dual receiving.Key knowledge point 4:The dual-send-dual-receive mode is an earlier application which is no longer adopted. The dual-receive-single-send mode is temporarily not much used on site.Key knowledge point 5:If the active PW of the PW dual-home is to bind the tunnel protection group, this protection group must be configured as 1:1 LSP protection.

Key knowledge point 1:For the case that RNC adopts the LAG active/standby mode:The active PW and the tunnel protection should exist at the same time to prevent the broken fiber inside the PTN network, however, at this moment, RNC does not perform switchover. The internal PTN network still can switch the service over to the active receiving node, ensuring that the service is not interrupted.Key knowledge point 2:For the case that RNC adopts the LAG load-sharing mode: The node that selectively receives PW adopts the dual-receive-single-send mode. For a base station, the LAG load sharing of RNC is branched out based on the BS IP addresses. Therefore, the node also adopts the singel-receive mode for a BS service stream. In this case, do not adopt the tunnel protection.Key knowledge point 3:The PW dual-homing protection switchover does not depends on APS for switchover other than the LOC and CSF switchover on the local end. The difference between 1:1 and 1+1 only lies in single receiving or dual receiving.Key knowledge point 4:The dual-send-dual-receive mode is an earlier application which is no longer adopted. The dual-receive-single-send mode is temporarily not much used on site.Key knowledge point 5:If the active PW of the PW dual-home is to bind the tunnel protection group, this protection group must be configured as 1:1 LSP protection.

Contents


PTN Protection Summary

Protection Status Description Key-Point Summary for Protection Configuration Protection Switchover Status Query

Protection Status Description SF: SF in the PTN network is detected by the OAM packet. Therefore, when

LOC or the mismerged, defective and mismatched MEP occurs on the local device, it is considered that the service signal received by the device fails.

SD: The SD in the PTN network is achieved by the pre-activated LM that detects the service packet loss rate either on the TMS layer or on the TMP layer. The near-end packet loss rate and the remote-end packet loss rate are used to compute ES/SES/UAS. If the packet loss rate is greater than 0, compute ES. If the packet loss rate is greater than 30%, compute SES.

Hold-off switchover: In some cases, the switchover is not expected to be performed once a fault occurs. Instead, we need to wait a while to confirm whether the fault is still there before performing switchover. This process is called the hold-off switchover. The waiting time is called the switchover hold-off time. This situation is commonly used for the PW protection to configure the hold-off time (step length: 100ms) when the tunnel protection and the PW protection co-exist.

Lock protection: No matter whether the active/standby channel is normal, the data are sent or received on the active channel regularly.

Force switch: When the stanby channel is normal, no matter whether the active channel is normal, switch over to the active channel to receive data.

Key-Point Summary for Protection Configuration

Linear/subnet protection

TMP OAM configuration of work protection

Configuration of tunnel linear protection group

Note: Currently, these two procedures of the linear protection and the subnet protection are conbined.

Here the difference of the linear and subnet configuration lies in the configuration in OAM and the protection group.The MEG mode of the tunnel in the linear configuration is END.The MEG mode of the tunnel in the subnet protection group is TCM.

Linear/subnet protection

TMP OAM configuration of work protection

Configuration of tunnel linear protection group

Note: Currently, these two procedures of the linear protection and the subnet protection are conbined.

Here the difference of the linear and subnet configuration lies in the configuration in OAM and the protection group.The MEG mode of the tunnel in the linear configuration is END.The MEG mode of the tunnel in the subnet protection group is TCM.

PW dual-homing protection

OAM configuration of the active/standby TMC (select CSF Insert and Extract)

Configure PW protection group on the protected node

PW dual-homing protection

OAM configuration of the active/standby TMC (select CSF Insert and Extract)

Configure PW protection group on the protected node

Ring network protection configuration

TMS configuration

TMS OAM MEG configuration

TMRP configuration (enable APS)

Ring tunnel configuration (one work tunnel corresponds to one ring tunnel)

Ring protection group configurationConfigure PE node once (one direction on protection ring)Configure P node twice (two directions on protection ring)

Ring network protection configuration

TMS configuration

TMS OAM MEG configuration

TMRP configuration (enable APS)

Ring tunnel configuration (one work tunnel corresponds to one ring tunnel)

Ring protection group configurationConfigure PE node once (one direction on protection ring)Configure P node twice (two directions on protection ring)

LAG port protection

Configure smartgroup.

Select the running status (static or dynamic) and the bound physial port of the smartgroup; configure the smartgroup type (active/standby, or load sharing).

LAG port protection

Configure smartgroup.

Select the running status (static or dynamic) and the bound physial port of the smartgroup; configure the smartgroup type (active/standby, or load sharing).

Protection Switchover Status Query Commonly used query command for the

linear protection switchover:

ZXR10(config)#show aps protect-config 1

Protect group id: 1

Active state: active

Running mode: network

APS current state: SIGNAL_FAIL_P <-

indicating that the SF alarm occurs on the

protection tunnel.

request bridge type: no switched

Protect mode:revertive, WTR time:1(min)

Protect switch:clear

Hold-off time:0(ms)

Commonly used query command for the ring

protection switchover:

ZXR10(config)#show aps mepg-config 1

TMRP id:1

Active state: active

running mode: network <- Default: network;

If it is local, it indicates that the APS packets

are not to be sent.

Aps-id: 1, east-aps-id: 2, west-aps-id: 3

East-tms:1, switch: null

West-tms: 2, switch: null

Ring switch mode: standard <- Default:

standard; other other values

Ring APS state: SWITCHING_SF of east tms

<- The red part indicates that the SF alarm

occurs on the eastward TMS.

request bridge type: switched

WTR time:1(min)

Hold-off time:0(ms)

Documents

PTN Protection Subject V1.0. Contents PTN Protection Type PTN Protection Principle and Application PTN Protection Summary