At the RIPE conference the was a talk about how MAC addresses starting with a 4or 6 may suffer from decreased performance because MPLS routers misinterpret the Ethernet packets as an IPv4/6 packet when load balancing over multiple links.

Presentation is here

One workaround would be to insert additional fields to prevent misinterpretation of the packets. Control words do the trick. Now, I know that control words are enabled on l2vpn connections on juniper by default, but I can't find any information regarding VPLS.

Does anyone know if control words are sent when using VPLS on juniper by default or if we can enable them?

2 Answers 2


negotiation of the control-word between the BGP VPLS PE routers is added in Juniper MX series starting from Junos 14.1. so only BGP-signaled VPLS.



I don't know for sure, but

set routing-instances red instance-type vpls protocols vpls control-word

commits for me on 12.3R2.5

and this is mentioned here:

On MX Series routers with the Channelized OC3/STM1 (Multi-Rate) Circuit Emulation MIC with SFP, Junos OS substantially supports RFC 4385, Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for Use over an MPLS PSN

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