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IS-IS route tagging

‎11-26-2016 03:49 PM

I have a question as i am not able to find any documentation anywhere so far for what i'm looking for. 

 

But, My question is, I Thought if you turned off traffic engineering on your is-is protocol that it would not tag any routes getting advertised out? 

 

So i have a lo0 interface with an IPv4 and v6 address on there, When i have the policy applied and traffic engineering enabled on the connecting router P1 i see the appropriate tag coming in for the loopback ips. IE 

 

 

root@P1# show protocols isis 
export tag-lo0;
interface ge-0/0/1.0;
interface ge-0/0/2.0;
interface ge-0/0/3.0;
interface ge-0/0/4.0;
interface ge-0/0/5.0;
interface lo0.0 {
    passive;
}

[edit]
root@P1# show policy-options policy-statement tag-lo0 
from interface lo0.0;
then {
    tag 200;
    accept;
}

 

 

root@PE12# run show route protocol isis | match tag
1.1.1.1/32 [IS-IS/15] 03:53:00, metric 10, tag 200
2001:db8::/128 *[IS-IS/15] 03:53:00, metric 10, tag 200

 

Now, If i just disable traffic engineering on the is-is protocol, I still see a tag for the ipv6 route but not the ipv4. 

 

root@PE12# run show route protocol isis | match tag
2001:db8::/128 *[IS-IS/15] 04:00:59, metric 10, tag 200

 

If i remove the policy from P1, It will not tag the ipv6 route. I was just wondering is this normal for the basic policy i have or does it appear to be a bug? 

 

5 REPLIES 5
Routing
Solution
Accepted by topic author robkuhn
‎11-27-2016 08:21 PM

Re: IS-IS route tagging

‎11-27-2016 03:25 AM

When ISIS Traffic Engineering is disabled, TLVs 22, 134, and 135 are suppressed from being sent

Tags for IPv4 routes  are in TLV re in 135 (sub-TLV 1).

 

For IPv6 routes the tags are in TLV 236. They are still present when you disable TE.

 

In all the cases check the ISIS DB: show isis database extensive and you will see what information is being flooded.

Routing

Re: IS-IS route tagging

‎11-27-2016 08:21 PM

Thanks, That clears it up for me. 

I thought disabling traffic engineering turned off all tagging. 

 

Routing

Re: IS-IS route tagging

‎12-03-2016 10:52 PM

Not sure if this will show up since it was marked solved, 

But, i had another question related to this. 

 

If i have both wide-metrics-only enabled, as well as traffic-engineering disabled, 

This is suppost to supress tlvs 2,22,128,134,135 from being sent. 

 

The documentation says it will basically be a loss of isis routing information for that level. 

 

Since i configured it on both level 1 and level 2 i shouldn't see those tlvs, or supposidly anything. 

 

Now, i do not see any routing information under the protocol isis, both the ipv4 and ipv6 table is blank. 

 

But, if i monitor traffic on the downstream router, i still see advertisements for the ipv6 interfaces as well as the tag that is set on the export policy as seen below.

 

IPv6 prefix: 2001:db9::1:2/127 Metric 10 Up
IPv6 prefix: 2001:db9::1:4/127 Metric 10 Up
IPv6 prefix: 2001:db9::1:0/127 Metric 10 Up
IPv6 prefix: 2001:db9::1:6/127 Metric 10 Up
IPv6 prefix: 2001:db9::1:8/127 Metric 10 Up
IPv6 prefix: 2001:db8::/128 Metric 0 Up
6 bytes of subtlvs
Administrative tag 1: 200

 

IPv6 reachability TLV #236, length: 139
IPv6 prefix: 2001:db9::1:2/127, Distribution: up, Metric: 10, Internal
IPv6 prefix: 2001:db9::1:4/127, Distribution: up, Metric: 10, Internal
IPv6 prefix: 2001:db9::1:0/127, Distribution: up, Metric: 10, Internal
IPv6 prefix: 2001:db9::1:6/127, Distribution: up, Metric: 10, Internal
IPv6 prefix: 2001:db9::1:8/127, Distribution: up, Metric: 10, Internal
IPv6 prefix: 2001:db8::/128, Distribution: up, Metric: 0, Internal, sub-TLVs present (6)
32-Bit Administrative tag subTLV #1, length: 4, 0x000000c8 (=200)

 

Does this make sence, or maybe its a bug in junosphere? Or am i missing a small detail somewhere?

Routing

Re: IS-IS route tagging

‎12-05-2016 05:15 AM

You are still advertising IPv6 reachability information (TLVs #232 or #236). You can disable it

set protocols isis no-ipv6-routing

 

Or I think that you could do the opposite which is to allow only IPv6 (and although the "main" topology is non-existing)

If you enable multi topology TLVs #229 I think you should see IPv6 routing information

set protocols isis topologies ipv6-unicast

Let me know if it worked.

 

 

Routing

Re: IS-IS route tagging

‎12-05-2016 09:02 AM

So that explains why i am still seeing the TLVs, 

But do you know why (Since its advertising those routes) it wouldn't be showing up in the route table on the downstream router?