Virtual Private LAN Service
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FD 100/320Gbps NT and FX NT IHub Services Guide
3HH-11985-AAAA-TQZZA Issue: 13
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Layer 2 MTU — derived from service vpls service-mtu parameter
• The same value must be used in all related BGP VPLS instances in the Remote PEs
to ensure the related pseudowires will come up.
• In order to interoperate with existing implementations if the received MTU value=0,
the MTU negotiation does not take place; the related pseudowire is setup to ignore
the MTU.
• Control Flag C — depending on the control-word setting in pseudowire-template
• Control Flag S — always 0
On reception the values of the parameters in the L2-Info extended community of the
BGP Update are compared with the settings from the corresponding
pseudowire-template. The following steps are used to determine the local
pseudowire-template:
• The RT values are matched to determine the pseudowire-template.
• If multiple pseudowire-template matches are found from the previous steps, the
first configured pseudowire-template will be considered.
• It is expected for most of the BGP VPLS use cases there will be no cases where
multiple RTs will be matched at the receiving end.
• If the values used for Layer 2 MTU or C Flag do not match, the pseudowire setup
fails.
The tools perform commands can be used simialrly as for BGP-AD to force the
application of changes in pseudowire-tempalte using the format described below:
tools perform service [id service id] eval-pw-templatepolicy-id
[allow-service-impact]
This command works as follows:
• In earlier releases, in BGP-ASD when the import RT policy changes a VPLS
shutdown followed by a no shutdown was required for the next pw-template-bin
match to be considered.
• The above command can also be used to apply the changes to the mapping
between pw-template-bind and import-rt. When used, the command checks if all
the bindings using this pseudowire template in the command context (service id,
if used) are still meant to use this policy. If the mapping has changed and
allow-service-impact is TRUE, then the old binding is removed and then re-added
with the new template.
5.11.3.1 Usage case example
Assuming the service vpls 100 bgp pw-template-bind 1 import-rt 100:50 was
removed, the following command can be used to remove the old pseudowire
bindings:
tools perform service id 100 eval-pw-template 1 allow-service-impact
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