Cisco Systems 1000 Series Manual De Usuario

Reverse Layer 2 Gateway Protocol

3.8.0S

Reverse L2GP (R-L2GP) is a variation of L2GP. In case of 
R-L2GP, the pseudo information of the R-L2GP is 
transmitted by nPEs, instead of uPEs. R-L2GP provides a 
mechanism to send out static preconfigured BPDUs on each 
ring access port of nPEs to stimulate a per-access ring 
instantiation of the protocol. R-L2GP enables the PEs to 
avoid the burden of running Multiple-instance Spanning 
Tree Protocol (MST) when multiple independent access 
networks that run MST connect to a pair of redundant PEs. 
In order for this to work, the pair of nPEs are programmed 
to send out BPDUs on the access ring ports in such a way 
that they appear to be either:

The root bridge itself (the bridge with the lowest bridge 
id/priority).

The bridge with the second lowest bridge ID/priority, 
and with a 0 cost path to the root.

The following sections provide information about this 
feature:

HDLC-Ethernet Interworking

3.13.0S

High-Level Data Link Control (HDLC)-Ethernet over 
MPLS is part of Any Transport over MPLS (AToM) 
solution. HDLC and Ethernet are two link-layer transport 
systems that utilize the AToM architecture. The feature 
describes how these two transport system can communicate 
with each other using the AToM framework. 

The following sections provide information about this 
feature: