Information About Serial Interface (X.21/V.35/RS-530/RS-449)
This following sections provide information about configuring serial interface (x.21/v.35/rs-530/RS-449) feature on the Cisco ASR 903 Series Router.
Overview of Configuring X.21/V.35/RS-530/RS-449
CESoPSN encapsulates structured signals as pseudowires over packet switched networks (PSNs). Emulation of signals saves PSN bandwidth and supports 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 the payload. The number of TDM frames to be used within the CESoP is a factor of the serial data size. For Nx64 kbps serial line, the number of timeslots in a given TDM frame are inferred based on the line speed.
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.
CEM provides a bridge between a time-division multiplexing (TDM) network and MPLS network. The router encapsulates the TDM data in the MPLS packets and sends the data over a CEM pseudowire to the remote provider edge (PE) router. Thus, CEM functions as a physical communication link across the packet network.
CEM dejitter buffer value can be configured to accommodate any delays in the MPLS network. Service policy can be applied to the CEM interface, only exp bit re-marking is supported in default class.
Configuring CEM Restriction
Not all combinations of payload size and dejitter buffer size are supported. If you apply an incompatible payload size or dejitter buffer size configuration, the router rejects it and reverts to the previous configuration.
The pseudowire utilizes Circuit Emulation Service over Packet-Switched Network (CESoPSN -RFC5086) in E1 mode to transport the x.21/v.35/rs-530/RS-449 traffic over MPLS network.
Migration from legacy network to MPLS network supports hitless traffic switch from active RSP to standby RSP.
It supports the serial data speed that are multiples of 64kbps. The maximum limit of speed can be 2048kbps.
Serial IM SPA must be installed.
PEs must be reachable over MPLS network.
Sync-E must be configured between pseudowire peers.
Specific combinations of payload size and dejitter buffer size are supported. If incompatible values are applied, the router reverts to the previous configuration.
Supported speeds are 64kbps, 128kbps, 256kbps, 512kbps, 1024kbps, and 2048kbps.
Serial IM does not support to configure pseudowire between local and remote PE with different speeds on sync (x.21/v.35/rs-530/RS-449) ports.
The transit of traffic is not supported from port 0 to 7. It is supported only from port 8 to 13.