Specifications

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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
For instructions on how to create an EoMPLS PW, see the “Configuring Transportation of Service Using
Ethernet over MPLS” section on page 4-87.
Limitations
When configuring an EoMPLS pseudowire on the Cisco MWR 2941, you cannot configure an IP address
on the same interface as the pseudowire.
Generic Routing Encapsulation (GRE) Tunneling
Generic routing encapsulation (GRE) is a tunneling protocol developed by Cisco that can encapsulate a
wide variety of protocol packet types inside IP tunnels, creating a virtual point-to-point link to Cisco
routers at remote points over an IP internetwork. GRE tunneling allows you to transport a pseudowire
over an IP backhaul network when MPLS routing is not available between a cell site (BTS or Node-B)
and an aggregation point (BSC or RNC). The Cisco MWR 2941 supports GRE encapsulation for the
following PW connection types:
• ATM over MPLS
• SAToP
• CESoPSN
• Ethernet over MPLS
The Cisco MWR 2941 implementation of GRE can interoperate with the Cisco 7600 router and provides
compliance with RFCs 2784 and 4023. The Cisco MWR 2941 supports up to 128 GRE tunnels. For more
information about how to configure GRE tunneling, see the “Configuring GRE Tunneling” section on
page 4-76.
Resilient Ethernet Protocol (REP)
A REP segment is a chain of ports connected to each other and configured with a segment ID. Each
segment consists of standard (nonedge) segment ports and two user-configured edge ports. A switch can
have only two ports belonging to the same segment, and each segment port can have only one external
neighbor. A segment can go through a shared medium, but on any link, only two ports can belong to the
same segment. REP is supported only on Layer 2 trunk interfaces.
Figure 1-2 shows an example of a segment consisting of six ports spread across four switches. Ports E1
and E2 are configured as edge ports. When all ports are operational (as in the segment on the left), a
single port is blocked, shown by the diagonal line. When there is a network failure, as shown in the
diagram on the right, the blocked port returns to the forwarding state to minimize network disruption.