[j-nsp] loop detection on EX4200

[Ben Dale]

On 23 Apr 2014, at 1:56 pm, Victor Sudakov <vas at mpeks.tomsk.su> wrote:

> Ben Dale wrote:
>> 
>>> No, LLDP does not work either across the multiplexer. If I configure a
>>> vlan tag on the "default" vlan on the EX42, LLDP starts seeing the
>>> EX42 on the other side.
>>> 
>>> That was the reason I had suggested that the multiplexer did not
>>> forward untagged frames.
>> 
>> That is certainly odd.  Even on a trunked interface with no native-vlan configured at all, LLDP PDUs should still be sent untagged:
>> 
>> bdale at elow-core-01# show interfaces ge-1/1/5                               
>> vlan-tagging;
>> unit 3830 {
>>    vlan-id 3830;
>>    family inet {
>>        address 10.237.18.29/31;
>>    }
>>    family mpls;
>> }
> 
> This is probably because your interface is in the "vlan-tagging" mode,
> while mine is "family ethernet-switching" mode.

I see the same behaviour on a 4200.  LLDP is always sent untagged:

comlinx at cesw01-all> show configuration interfaces ge-0/0/2  
description "Link to BELL";
unit 0 {
    family ethernet-switching;
}

### no VLAN-ID configured on default:

comlinx at cesw01-all> show vlans default  
Name           Tag     Interfaces
default       
                       ae10.0, ge-0/0/0.0*, ge-0/0/2.0*, ge-0/0/3.0, ge-0/0/11.0
{master:0}

comlinx at cesw01-all> monitor traffic interface ge-0/0/2 layer2-headers matching "ether dst 01:80:c2:00:00:0e"  
verbose output suppressed, use <detail> or <extensive> for full protocol decode
Address resolution is ON. Use <no-resolve> to avoid any reverse lookup delay.
Address resolution timeout is 4s.
Listening on ge-0/0/2, capture size 96 bytes

14:08:16.031851 Out 80:71:1f:e2:17:05 > 01:80:c2:00:00:0e, ethertype LLDP (0x88cc), length 74: LLDP, name cesw01-all, length 60
	[|LLDP]