Virtual Private LAN Service232FD 100/320Gbps NT and FX NT IHub Services Guide3HH-11985-AAAA-TQZZA Issue: 13• 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 PEsto 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 ignorethe MTU.• Control Flag C — depending on the control-word setting in pseudowire-template• Control Flag S — always 0On reception the values of the parameters in the L2-Info extended community of theBGP Update are compared with the settings from the correspondingpseudowire-template. The following steps are used to determine the localpseudowire-template:• The RT values are matched to determine the pseudowire-template.• If multiple pseudowire-template matches are found from the previous steps, thefirst configured pseudowire-template will be considered.• It is expected for most of the BGP VPLS use cases there will be no cases wheremultiple RTs will be matched at the receiving end.• If the values used for Layer 2 MTU or C Flag do not match, the pseudowire setupfails.The tools perform commands can be used simialrly as for BGP-AD to force theapplication 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 VPLSshutdown followed by a no shutdown was required for the next pw-template-binmatch to be considered.• The above command can also be used to apply the changes to the mappingbetween pw-template-bind and import-rt. When used, the command checks if allthe 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 andallow-service-impact is TRUE, then the old binding is removed and then re-addedwith the new template.5.11.3.1 Usage case exampleAssuming the service vpls 100 bgp pw-template-bind 1 import-rt 100:50 wasremoved, the following command can be used to remove the old pseudowirebindings:tools perform service id 100 eval-pw-template 1 allow-service-impact
