Cisco ME-3600X-24CX Series Switch Chassis Configuration Guide, Release 15.2(2)S
Configuring Pseudowire
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Configuring Pseudowire

Table Of Contents

Configuring Pseudowire

Pseudowire Overview

Circuit Emulation Overview

Structure-Agnostic TDM over Packet

Circuit Emulation Service over Packet-Switched Network

Transportation of Service Using Ethernet over MPLS

Configuring Structure-Agnostic TDM over Packet (SAToP)

Configuring Circuit Emulation Service over Packet-Switched Network (CESoPSN)

Configuring Pseudowire Redundancy

Verifying the Interface Configuration


Configuring Pseudowire


This chapter provides information about configuring pseudowire features on the Cisco ME 3600X 24CX Series Switch. It contains the following sections:

Pseudowire Overview

Configuring Structure-Agnostic TDM over Packet (SAToP)

Configuring Circuit Emulation Service over Packet-Switched Network (CESoPSN)

Configuring Pseudowire Redundancy

Verifying the Interface Configuration

Pseudowire Overview

The following sections provide an overview of pseudowire support on the Cisco ME 3600X 24CX Series Switch.

Circuit Emulation Overview

Circuit Emulation (CEM) is a technology that provides a protocol-independent transport over IP networks. It enables proprietary or legacy applications to be carried transparently to the destination, similar to a leased line.

The Cisco ME 3600X 24CX Series Switch supports two pseudowire types that utilize CEM transport: Structure-Agnostic TDM over Packet and Circuit Emulation Service over Packet-Switched Network. The following sections provide an overview of these pseudowire types.

Structure-Agnostic TDM over Packet

SAToP encapsulates TDM bit-streams (T1, E1) as PWs over PSNs. It disregards any structure that may be imposed on streams, in particular the structure imposed by the standard TDM framing.

The protocol used for emulation of these services does not depend on the method in which attachment circuits are delivered to the PEs. For example, a T1 attachment circuit is treated the same way for all delivery methods, including: PE on copper, mapped into a virtual tributary of a SONET/SDH circuit, or carried over a network using unstructured Circuit Emulation Service (CES). Termination of specific carrier layers used between the PE and circuit emulation (CE) is performed by an appropriate network service provider (NSP).

In the SAToP mode the interface is considered as a continuous framed bit stream. The packetization of the stream is done according to IETF RFC 4553. All signaling is carried out transparently as a part of a bit stream. Figure 6-1 shows the frame format in Unstructured SAToP mode.

Figure 6-1 Unstructured Mode Frame Format

Table 6-1 shows the payload and jitter limits for the T1 lines in the SAToP frame format.

Table 6-1 SAToP T1 Frame: Payload and Jitter Limits

Maximum Payload
Maximum Jitter
Minimum Jitter
Minimum Payload
Maximum Jitter
Minimum Jitter

960

320

10

192

64

2


Table 6-2 shows the payload and jitter limits for the E1 lines in the SAToP frame format.

Table 6-2 SAToP E1 Frame: Payload and Jitter Limits

Maximum Payload
Maximum Jitter
Minimum Jitter
Minimum Payload
Maximum Jitter
Minimum Jitter

1280

320

10

256

64

2


For instructions on how to configure SAToP, see Configuring Structure-Agnostic TDM over Packet (SAToP).

Circuit Emulation Service over Packet-Switched Network

CESoPSN encapsulates structured (NxDS0) TDM signals as PWs over public switched networks (PSNs). It complements similar work for structure-agnostic emulation of TDM bit streams, such as SAToP. Emulation of NxDS0 circuits saves PSN bandwidth and supports DS0-level grooming and distributed cross-connect applications. It also enhances resilience of CE devices due to the effects of loss of packets in the PSN.

CESoPSN identifies framing and sends only the payload, which can either be channelized T1s within DS3 or DS0s within T1. DS0s can be bundled to the same packet. The CESoPSN mode is based on IETF RFC 5086.

CESoPSN supports channel-associated signaling (CAS) for E1 and T1 interfaces. CAS provides signaling information within each DS0 channel as opposed to using a separate signaling channel. CAS also referred to as in-band signaling or robbed bit signaling.

Each supported interface can be configured individually to any supported mode. The supported services comply with IETF and ITU drafts and standards.

Figure 6-2 shows the frame format in CESoPSN mode.

Figure 6-2 Structured Mode Frame Format

Table 6-3 shows the payload and jitter for the DS0 lines in the CESoPSN mode.

Table 6-3 CESoPSN DS0 Lines: Payload and Jitter Limits

DS0
Maximum Payload
Maximum Jitter
Minimum Jitter
Minimum Payload
Maximum Jitter
Minimum Jitter

1

40

320

10

32

256

8

2

80

320

10

32

128

4

3

120

320

10

33

128

4

4

160

320

10

32

64

2

5

200

320

10

40

64

2

6

240

320

10

48

64

2

7

280

320

10

56

64

2

8

320

320

10

64

64

2

9

360

320

10

72

64

2

10

400

320

10

80

64

2

11

440

320

10

88

64

2

12

480

320

10

96

64

2

13

520

320

10

104

64

2

14

560

320

10

112

64

2

15

600

320

10

120

64

2

16

640

320

10

128

64

2

17

680

320

10

136

64

2

18

720

320

10

144

64

2

19

760

320

10

152

64

2

20

800

320

10

160

64

2

21

840

320

10

168

64

2

22

880

320

10

176

64

2

23

920

320

10

184

64

2

24

960

320

10

192

64

2

25

1000

320

10

200

64

2

26

1040

320

10

208

64

2

27

1080

320

10

216

64

2

28

1120

320

10

224

64

2

29

1160

320

10

232

64

2

30

1200

320

10

240

64

2

31

1240

320

10

248

64

2

32

1280

320

10

256

64

2


For instructions on how to configure SAToP, see Configuring Structure-Agnostic TDM over Packet (SAToP).

Transportation of Service Using Ethernet over MPLS

Ethernet over MPLS (EoMPLS) PWs provide a tunneling mechanism for Ethernet traffic through an MPLS-enabled Layer 3 core network. EoMPLS PWs encapsulate Ethernet protocol data units (PDUs) inside MPLS packets and use label switching to forward them across an MPLS network. EoMPLS PWs are an evolutionary technology that allows you to migrate packet networks from legacy networks while providing transport for legacy applications. EoMPLS PWs also simplify provisioning, since the provider edge equipment only requires Layer 2 connectivity to the connected customer edge (CE) equipment. The Cisco ME 3600X 24CX Series Switch implementation of EoMPLS PWs is compliant with the RFC 4447 and 4448 standards.

The Cisco ME3600-24CX Switch supports VLAN rewriting on EoMPLS PWs. If the two networks use different VLAN IDs, the router rewrites PW packets using the appropriate VLAN number for the local network.

Configuring Structure-Agnostic TDM over Packet (SAToP)

Follow these steps to configure SAToP on the Cisco ME 3600X 24CX Series Switch:

 
Command
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

controller [T1|E1] 0/1
Example:

Router(config-controller)# controller t1

Configures the T1 or E1 interface.

Step 4 

cem-group group-number {unframed | timeslots timeslot }

Example:

Router(config-if)# cem-group 4 unframed

Assigns channels on the T1 or E1 circuit to the CEM channel. This example uses the unframed parameter to assign all the T1 timeslots to the CEM channel.

Step 5 

Router(config)# interface CEM0/4
Router(config-if)# no ip address

Router(config-if)# cem 4

Defines a CEM group.

Step 6 

Router(config-if)# xconnect 30.30.30.2 304 encapsulation mpls

Binds an attachment circuit to the CEM interface to create a pseudowire. This example creates a pseudowire by binding the CEM circuit 304 to the remote peer 30.30.2.304.

Step 7 

exit

Example:
Router(config)# exit

Router#

Exits configuration mode.


Note When creating IP routes for a pseudowire configuration, we recommend that you build a route from the xconnect address (LDP router-id or loopback address) to the next hop IP address, such as ip route 30.30.30.2 255.255.255.255 1.2.3.4.


Configuring Circuit Emulation Service over Packet-Switched Network (CESoPSN)

Follow these steps to configure CESoPSN on the Cisco ME 3600X 24CX Series Switch.

 
Command
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

Router(config)# controller [e1|t1] 
0/0

Router(config-controller)#

Enters configuration mode for the E1 or T1 controller.

Step 4 

Router(config-controller)# cem-group 5 timeslots 1-24

Assigns channels on the T1 or E1 circuit to the circuit emulation (CEM) channel. This example uses the timeslots parameter to assign specific timeslots to the CEM channel.

Step 5 

Router(config-controller)# exit

Router(config)#

Exits controller configuration.

Step 6 

Router(config)# interface CEM0/5
Router(config-if-cem)# cem 5
 
        

Defines a CEM channel.

Step 7 

Router(config-if-cem)# xconnect 30.30.30.2 305 encapsulation mpls

Binds an attachment circuit to the CEM interface to create a pseudowire. This example creates a pseudowire by binding the CEM circuit 5 to the remote peer 30.30.30.2.

Note When creating IP routes for a pseudowire configuration, we recommend that you build a route from the xconnect address (LDP router-id or loopback address) to the next hop IP address, such as ip route 30.30.30.2 255.255.255.255 1.2.3.4.

Step 8 

Router(config-if-cem)# exit

Router(config)#

Exits the CEM interface.

Step 9 

exit

Example:
Router(config)# exit

Router#

Exits configuration mode.

Configuring Pseudowire Redundancy

A backup peer provides a redundant pseudowire (PW) connection in the case that the primary PW loses connection; if the primary PW goes down, the Cisco ME 3600X 24CX Series Switch diverts traffic to the backup PW. This feature provides the ability to recover from a failure of either the remote PE router or the link between the PE router and CE router.

Figure 6-3 shows an example of pseudowire redundancy.

Figure 6-3 Pseudowire Redundancy


Note You must configure the backup pseudowire to connect to a router that is different from the primary pseudowire.


Follow these steps to configure a backup peer:

 
Command
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Enters global configuration mode.

Step 3 

pseudowire-class [pw-class-name]

Specify the name of a Layer 2 pseudowire class and enter pseudowire class configuration mode.

Step 4 

encapsulation mpls

Specifies MPLS encapsulation.

Step 5 

interface cem card/number

Enters configuration mode for the cem interface.

Note The card number is always 0.

Step 6 

Router(config-if)# xconnect 1.1.1.2 101 encapsulation mpls

Binds the Ethernet port interface to an attachment circuit to create a pseudowire.

Step 7 

Router(xconnect)# backup peer peer-router-ip-address vcid [pw-class pw-class name]

Defines the address and VC of the backup peer.

Step 8 

exit

Exits configuration mode.

Verifying the Interface Configuration

You can use the following commands to verify your pseudowire configuration:

show cem circuit—Displays information about the circuit state, administrative state, the CEM ID of the circuit, and the interface on which it is configured. If xconnect is configured under the circuit, the command output also includes information about the attached circuit.

Router# show cem circuit ? 
  <0-504>    CEM ID
  detail     Detailed information of cem ckt(s)
  interface  CEM Interface
  summary    Display summary of CEM ckts
  |          Output modifiers
 
   
 
   
Router# show cem circuit 
CEM Int.       ID   Line      Admin     Circuit         AC  
-------------------------------------------------------------- 
CEM0/1				1    UP        UP        ACTIVE          --/--
CEM0/1				2    UP        UP        ACTIVE          --/--
CEM0/1				3    UP        UP        ACTIVE          --/--
CEM0/1				4    UP        UP        ACTIVE          --/--
CEM0/1				5    UP        UP        ACTIVE          --/--
 
   

show cem circuit—Displays the detailed information about that particular circuit.

Router# show cem circuit 1 
CEM0/1, ID: 1, Line State: UP, Admin State: UP, Ckt State: ACTIVE
Idle Pattern: 0xFF, Idle cas: 0x8, Dummy Pattern: 0xFF
Dejitter: 5, Payload Size: 40
Framing: Framed, (DS0 channels: 1-5)
Channel speed: 56
CEM Defects Set
Excessive Pkt Loss RatePacket Loss 
 
   
Signalling: No CAS
Ingress Pkts:    25929                Dropped:             0                   
Egress Pkts:     0                    Dropped:             0                   
CEM Counter Details
Input Errors:    0                    Output Errors:       0                   
Pkts Missing:    25927                Pkts Reordered:      0                   
Misorder Drops:  0                    JitterBuf Underrun:  1                   
Error Sec:       26                   Severly Errored Sec: 26                  
Unavailable Sec: 5                    Failure Counts:      1                   
Pkts Malformed:  0
 
   

show cem circuit summary—Displays the number of circuits which are up or down per interface basis.

Router# show cem circuit summary 
CEM Int.       Total Active  Inactive
--------------------------------------
CEM0/1				 5     5       0
 
   
 
   

show running configuration—The show running configuration command shows detail on each CEM group.