OCx CEM Interface Module Configuration Guide, Cisco IOS XE 17 (Cisco ASR 900 Series)
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This chapter provides a high-level description and restricions for the following OCx CEM interface modules:
1 port OC-48/STM-16 or 4 port OC-12/OC-3 / STM-1/STM-4 + 12 port T1/E1 + 4 port T3/E3 CEM Interface Module (A900-IMA3G-IMSG)
1-Port OC-192 or 8-Port Low Rate CEM Interface Module (A900-IMA8S1Z-CX)
ASR 900 1-Port OC-192 or 8-Port Low Rate CEM 20G Bandwidth Interface Module (A900-IMA1Z8S-CXMS)
Configuring Support of 1 port OC-48/STM-16 or 4 port OC-12/OC-3 / STM-1/STM-4 + 12 port T1/E1 + 4 port T3/E3 CEM Interface
Module
The 1 port OC-48/STM-16 or 4 port OC-12/OC-3 / STM-1/STM-4 + 12 port T1/E1 + 4 port T3/E3 CEM Interface Module has 12XDS1,
4XDS3, electrical interfaces, and 4XSFP ports that can provide multiple functions such as 1XOC-48/12/3 and 3XOC-12/3. The
maximum speed supported on OCx ports is OC-48. The interface module supports a maximum of 3G CEM traffic.
Note
In addition to support on RSP2 module, the IM is supported on RSP3 from the Cisco IOS XE 16.9.x release.
Configuring Support of 1-Port OC-192 or 8-Port Low Rate CEM Interface Module
The OC-192 interface module with 8-port low rate CEM interface module delivers one active port of OC192 or STM-64 connectivity,
or up to eight ports of OC3/12 or STM-1/-4 or up to 4 ports of OC48 or STM-16 connectivity on the router with RSP3. The module
can be clocked from a line or from an internal clock source. This module delivers true high density, multiservice and multi-rate
capabilities in a small form factor. The interface module can be software configured as either Synchronous Optical Networking
(SONET) mode or Synchronous Digital Hierarchy (SDH) mode per module in the ASR 900 Series configuration.
Configuring Support for ASR 900 1-Port OC-192 or 8-Port Low Rate CEM 20G Bandwidth Interface Module (A900-IMA1Z8S-CXMS)
The ASR 900 1-Port OC-192 or 8-Port Low Rate CEM 20G Bandwidth Interface Module (A900-IMA1Z8S-CXMS) is supported on the RSP3 module and has the capability for SONET or SDH termination with SAToP, CESoP, and CEP traffic types.
Note
The Ethernet and Multiservice Gateway features are not supported on this IM for the Cisco IOS XE 16.12.1 Release.
The IM is capable of processing a maximum of 20G with different types of traffic such as 10G CEM, 2.5G iMSG, 2.5G Ethernet,
and 6.9Mbps DCC. However for the Cisco IOS XE Release 16.12.1, only the 10G CEM traffic is supported. In the 10G mode, 7.5G
CEM traffic is supported.
In this IM, all the eight 1G ports can be configured as OC-48 and you can utilize a maximum of 192 STS-1.
The ASR 9001-port OC-192 or 8-port Low Rate CEM 20G Bandwidth interface module functions similar to the 1-port OC-192/STM-64 or 8-port
OC-3/12/48/STM-1/-4/-16 interface module. The configurations remain the same.
The following TDM features are supported:
SNMP
Local, network, or remote loopback
BERT (both system and line). The system side BERT is not supported in the framed SAToP mode.
OH config
Network synchronization
SSM
Shut at port and CEM-group level
DCC is supported starting from Cisco IOS XE Amsterdam 17.3.1 release
Interworking Multiservice Gateway Access Circuit Redundancy (iMSG ACR) support starting with the Cisco IOS XE 17.3.1 release.
The following TDM features are supported starting from Cisco IOS XE Bengaluru 17.4.1 release:
APS and non-APS for SDH and SONET for iMSG IPv6 interworking.
NxDS0 iMSG IPv4 and NxDS0 APS iMSG IPv4.
UPSR IPv6.
IPv4 with VLAN handoff for cross connect and local connect.
The CEM features such as SAToP, CESoP, and CEP are supported in the following modes:
Unprotected CEM with ACR or DCR are supported in the following modes:
T1, T3, E1, E3, DS0, DS1, and DS3
CEM Payload size configurable.
APS CEM with ACR or DCR are supported in the following modes
DS0, DS1, DS3, T1, T3, E1, E3, AU-3, and AU-4
CEM payload size configurable.
UPSR at VT or STS mode.
DS1 (with VT Protection) or DS3 (STS Protection) with ACR or DCR
CEM Class with configurable payload size or jitter buffer
Modes of Operation
The interface module operates in following two modes:
Single XFI or 10 G mode
Dual XFI or 20 G mode
Single XFI or 10 G mode
Consider the following requirement while working on the 10 G mode:
OC-192 or SFP+ port is supported on the 10G GE port. In the 10G mode, 7.5G for CEM traffic is supported.
If bandwidth is available to accommodate a particular circuit or Ethernet port, then configuration is allowed, and it can
be performed. Otherwise, the configuration is rejected due to bandwidth limitation.
When there is a change in the payload size, the required bandwidth gets modified accordingly. This in turn checks for the
bandwidth and if the sufficient bandwidth is not available, the configuration is rejected.
You can remove or delete the existing configuration from the port and perform new configuration on the port.
Dual XFI or 20 G mode
You can convert the IM into dual mode. In 20G mode of operation, channelized (xfi0) and non-channelized (xfi1) bandwidth are
available.
Enter the following commands to convert into dual mode and then reload the IM:
Consider the following requirements while working on the 20-G mode:
For configuring CEM group, the software performs bandwidth check. If the required bandwidth is not available, you cannot configure
the CEM group.
If a maximum capacity configuration is already performed on the IM and you update the payload size, then the update is not
accepted on the same channel (xfi). You need to remove some configurations on circuits and then update the payload again.
For slot compatibility, refer Supported RSP and Slots in the Cisco ASR 900 Series Routers and Cisco Interface Module Hardware Installation Guide.
Restrictions and Limitations for ASR 900 1-Port OC-192 or 8-Port Low Rate CEM 20G Bandwidth Interface Module (A900-IMA1Z8S-CXMS)
Feature Restrictions
The following features are not supported:
Ethernet
EOS L1 or L2
MS features are not supported for the Cisco IOS XE 16.12.1 release. Starting with the Cisco IOS XE Amsterdam 17.3.1 release,
MS features are supported.
DCC is not supported until the Cisco IOS XE 16.12.1 release.
IPv4 or IPv6 iMSG is not supported for the Cisco IOS XE 16.12.1 release.
Starting with the Cisco IOS XE Amsterdam 17.3.1 release, IPv4 iMSG is supported.
Starting with the Cisco IOS XE Bengaluru 17.4.1 release, IPv6 iMSG is supported.
For iMSG IPv6 MTU, the change in configuring MTU value is not supported. Ensure that you configure the circuit with the default
MTU value.
MLPPP for serial interface is not supported for the Cisco IOS XE Amsterdam 17.3.1 release.
STS-192c or VC-4-64c concatenation
Low-order path concatenation (VCAT)
Fractional CEP
BLSR for SONET or MSSP ring for SDH
SyncE and PTP Support on EoS (L1 or L2/L3 Terminated)
Card level protection
Nonstandard concatenation such as STS-6c, STS-9c, STS-15c, STS-18c, and so on
APS or MSP 1:N, where N is greater than 1.
TSOP support
Auto detection support
SONET to SDH and SDH to SONET Translation
CAS Signaling
HSPW
Scrambling is not supported in the POS mode.
In A900-IMA1Z8S-CXMS, invalid FE flag gets asserted for the current interval when the controller is shut and no shut.
Management Restrictions
The following are some management restrictions to consider while configuring the module:
The ports can be configured and used regardless of available backplane bandwidth or HO Path resources.
Provisioning a new CEM circuit and payload size change to the new CEM circuit is allowed as long as bandwidth is available.
Gigabit Ethernet configuration is allowed if required bandwidth is available. Bandwidth reallocation can be performed based
on some following scenarios:
The required bandwidth is not available on channelized xfi, but sufficient bandwidth is available on nonchannelized xfi. In
such cases, you should remove some configuration from circuits on the channelized xfi and then provision Gigabit Ethernet
followed by CEM circuit provision.
Scale Restrictions
The maximum number of supported VT1.5 CESoP circuits are 672 per interface module for Cisco IOS XE 16.12.x release.
For the Cisco IOS XE Amsterdam 17.3.1 release, a maximum of 1000 serial interfaces can be configured on RSP2 module as 1000
internal VLANs are reserved for serial interfaces. The same scale limit is applicable for RSP3 module.
For the Cisco IOS XE Amsterdam 17.3.1 release, CEM FPGA supports up to 1016 data channels per interface module.
For the Cisco IOS XE Amsterdam 17.3.x release, a maximum of 5376 ACR and DCR session scale is supported on the Cisco 1-port OC-192 Interface module or 8-port Low Rate Interface Module (ASR
900 Combo 8-port SFP GE and 1-port 10GE IM with CEM, 10G). For releases before the Cisco IOS XE Amsterdam 17.3.1 release,
only 2000 session are supported.
Table 1. Dual-Mode Restrictions for Gigabit Ethernet port
Circuit Type
Scale Supported
DS1 SAToP
2800
VT 1.5 CEP Pseudowire
2800
Gigabit Ethernet
1 x 10 G and 8 x 1 G
ACR or DCR
2000 per interface module
DS1 CESoP Pseudowire
672 per interface module
Features supported on OCx CEM Interface Module
Table 2. Features supported on OCx CEM Interface Module on ASR 900 Series Routers
Restrictions for Configuring OCx CEM Interface Modules
Mixed mode support, for example, T1 and E1 or T3 and E3 or SONET and SDH simultaneously on different ports is not available.
E1 or E3, Unidirectional Path Switching Ring (UPSR), and Data Communication Channel (DCC) are not supported.
Multiservice functionality: MLPPP, FR, and MLFR are not supported.
Starting with Cisco IOS XE Amsterdam 17.1.x, MLPPP is supported.
EoS and EoPDH are not supported.
The configure replace command is not supported.
On RSP3 module, the CEM OCx IM is not supported in slots 0 and 1.
On the Cisco ASR907 router, the CEM OCx IM is not supported in the default license mode but the IM is supported in the service-offload
license mode.
Synchronization Status Message (SSM) is not supported on T3 ports for 48-port T3 and E3 CEM IM and 1-port OC-48/STM-16 or
4-port OC-12/OC-3/STM-1/STM-4 + 12-port T1/E1 + 4-port T3/E3 CEM IM.
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