Specifications

1-32
Cisco MWR 2941 Mobile Wireless Edge Router Software Configuration Guide, Release 12.2(33)MRB
OL-21227-02
Chapter 1 Cisco MWR 2941 Router Overview
Features
MLPPP Optimization Features
The Cisco MWR 2941 supports several features that improve the performance of Multilink
Point-to-Point Protocol (MLPPP) connections and related applications such as PWE3 over MLPPP and
IP over MLPPP.
Distributed Multilink Point-to-Point Protocol (dMLPPP) Offload
Distributed Multilink Point-to-Point Protocol (dMLPPP) allows you to combine T1 or E1 connections
into a bundle that has the combined bandwidth of all of the connections in the bundle, providing
improved capacity and CPU utilization over MLPPP. The dMLPPP offload feature improves the
performance for traffic in dMLPPP applications such as PWE3 over MLPPP and IP over MLPPP by
shifting processing of this traffic from the main CPU to the network processor.
The Cisco MWR 2941 supports up to four serial links per T1/E1 connection and up to 24 MLPPP
bundles. You can use the fixed T1/E1 ports to create up to 64 MLPPP links; if you install two four-port
T1/E1 HWICs, you can create up to 96 MLPPP links.
The MWR 2941 implementation of multilink (dMLPPP) uses interleaving to allow short, delay-sensitive
packets to be transmitted within a predictable amount of time. Interleaving allows the MWR 2941 to
interrupt the transmission of delay-insensitive packets in order to transmit delay-sensitive packets. You
can also adjust the responsiveness of the MWR 2941 to delay-sensitive traffic by adjusting the maximum
fragment size; this value determines the maximum delay that a delay-sensitive packet can encounter
while the MWR 2941 transmits queued fragments of delay-insensitive traffic.
Multiclass MLPPP
The MWR 2941 implementation of dMLPPP also supports Multiclass MLPPP. Multiclass MLPPP is an
extension to MLPPP functionality that allows you to divide traffic passing over a multilink bundle into
several independently sequenced streams or classes. Each multiclass MLPPP class has a unique
sequence number, and the receiving network peer processes each stream independently. The multiclass
MLPPP standard is defined in RFC 2686.
The MWR 2941 supports the following multiclass MLPPP classes:
• Class 0–Data traffic that is subject to normal MLPPP fragmentation. Appropriate for
non-delay-sensitive traffic.
• Class 1–Data traffic that can be interleaved but not fragmented. Appropriate for delay-sensitive
traffic such as voice.
For instructions on how to configure MLPPP backhaul, see the “Configuring MLPPP Backhaul” section
on page 4-49.
Note The Cisco MWR 2941 does not support some PPP and MLPPP options when the bundle is offloaded to
the network processor; you can retain these options by disabling MLPPP and IPHC offloading for a
given bundle. For more information, see the “MLPPP Offload” section on page 4-58.
Note The output for the show ppp multilink command for an offloaded MLPPP bundle differs from the
output for a non-offloaded bundle. For more information, see Appendix B, “Cisco MWR 2941 Router
Command Reference.”