[j-nsp] loop detection on EX4200

[Victor Sudakov]

I have just had a funny experience on an EX4200 switch.

An Avara ENT100 multiplexer is connected to ge-0/0/22 on the
EX4200. By mistake, an E1 port on the ENT100 was physically looped.
This resulted in an Ethernet loop in all the vlans which were active
on the ge-0/0/22 port, which the EX4200 was unable to prevent.

Cisco switches can detect such conditions by sending special loopback
keepalives (Ether type 0x9000) and put the interface into errdisabled
state. Is there a similar feature in Juniper switches?

Thank you for any input.

-- 
Victor Sudakov,  VAS4-RIPE, VAS47-RIPN
sip:sudakov at sibptus.tomsk.ru