Configuring Pseudowires; Vpls Path Selection Process For Pe Routers; Chapter 6 Configuring Pseudowires - Juniper EX9200 Features Manual

CHAPTER 6

Configuring Pseudowires

VPLS Path Selection Process for PE Routers

Copyright © 2016, Juniper Networks, Inc.
VPLS Path Selection Process for PE Routers on page 57
Configuring Static Pseudowires for VPLS on page 59
The VPLS path selection process is used to select the best path between a remote PE
router and a local PE router in a VPLS network. This path selection process is applied to
routes received from both single-homed and multi-homed PE routers.
NOTE: In the VPLS documentation, the word router in terms such as PE router
is used to refer to any device that provides routing functions.
When the VPLS path selection process is complete, a PE router is made the designated
VPLS edge (VE) device. The designated VE device effectively acts as the endpoint for
the VPLS pseudowire that is signaled from the remote PE router. Once a PE router is
made the designated VE device, a pseudowire can be signaled between the remote PE
router and the local PE router and then VPLS packets can begin to flow between the PE
routers.
Routes from multihomed PE routers connected to the same customer site share the
same site ID, but can have different route distinguishers and block offsets. You can alter
the configurations of the route distinguishers and block offsets to make a router more
likely or less likely to be selected as the designated VE device.
On each PE router in the VPLS network, the best path to the CE device is determined by
completing the following VPLS path selection process on each route advertisement
received:
If the advertisement has the down bit set to 0, the advertisement is discarded.
1.
Select the path with a higher preference. The preference attribute is obtained from
2.
the site-preference configured using the
routing-instances routing-instance-name protocols vpls site site-name]
If the site preference is 0, the preference attribute is obtained from the local preference.
If the preference values are the same, select the path with the lower router ID.
3.
site-preference statement at the [edit
hierarchy level.
57