Do VPLS and VPWS services transfer STP frames? How about other L2 control frames? Can two geographically dispersed sites have one STP region over any L2VPN?

  • 3
    Yes. other L2 control frames? also yes. AFAIK, CDP, LLDP... all of that is transfered.
    – manish ma
    Nov 6, 2021 at 7:40

1 Answer 1


Normally yes, VPLS and VPWS should be transparent to all L2 frames. BPDUs might not be supported by all providers, so you'd want to check the SLA.

Alternatively, you should consider routing your traffic instead of bridging it. Routing removes the need to block redundant links and makes them productive.

  • 2
    This is definitely a "your mileage my vary" situation.
    – Ricky
    Nov 6, 2021 at 10:47
  • 2
    +1 to routing where possible. Also need to take into account that some providers MAY specifically block specific protocol control frames (e.g. STP BPDUs or even LLDP) through pseudowires. Best to ask your provider for technical specifications that details specific protocols and ether types that will be forwarded.
    – ditrapanij
    Nov 7, 2021 at 4:34
  • Actually, I didn't get why routing has an advantage over L2VPN. At least L2VPN must have some advantages too... I have heard from a tech person that small customers (like branches of stores or banks) use L3VPN and bigger customers (like ISPs) use L2VPN. @ditrapanij
    – A.A
    Nov 7, 2021 at 10:55
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    @A.A The only advantage a large L2 segment has is that's it's a large L2 segment. Any device can discover anything by broadcast and talk to any other device 'directly'. L2 doesn't scale well (1000+ nodes, anyone?), pollutes your large broadcast domain with said broadcasts, provides little control over what's permitted and what isn't (zoning!), disables many QoS mechanisms, and last but not least, doesn't support redundant or even load-balanced meshing. L2VPN may look simpler and more feasable with just two locations but it quickly becomes an absolute nightmare beyond that.
    – Zac67
    Nov 7, 2021 at 11:01
  • 1
    From the ISP perspective, it might look like the customers are using (more transparent) L2 links but especially larger clients won't ever use those to span large broadcast domains.
    – Zac67
    Nov 7, 2021 at 11:03

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