From: Dillon Yang (dillony@gmail.com)
Date: Fri Jul 15 2005 - 13:21:23 GMT-3
Hi, John
Please ignore the my previous post to yourself, its a mistake.
and about the "experience" , do you mean the leaking route? like this:
redistribute isis ip level?2 into level?1
distribute?list <100?199> metric?style wide
I dont think it is best for a transit area to distinguish the original route and the passing route.
TIA
dillon
----- Original Message -----
From: "John Do" <mcseccnp03@yahoo.com>
To: "Dillon Yang" <dillony@gmail.com>
Sent: Friday, July 15, 2005 12:07 PM
Subject: Re: Doyle's comment vs ISIS external route
> Dillon,
>
> There are couple of ways that I know to prevent optimal routing in IS-IS. You need to filter out L1 route and then leak L2 route into L1(metric wide). If you need me to lab this up and present to you a more detail information let me know. But if you want to experience and learn for yourself then that will be the way to learn.
>
> Dillon Yang <dillony@gmail.com> wrote:
> Hi, Paresh:
>
> Thanks! It is may be the answer.
> But I want a way to distinguish the external route for preventing loop, for the 12.2 dont support tag, you know. Then any advice on the distinction?
>
> TIA
> dillon
>
>
>
> ----- Original Message -----
> From: "Paresh Khatri"
>
> To: "Dillon Yang" ; "Group Study"
> Sent: Friday, July 15, 2005 10:11 AM
> Subject: RE: Doyle's comment vs ISIS external route
>
>
> Hi Dillon,
>
> Doyle is both right (from a standards perspective) and wrong (from a Cisco perspective).
>
> If you read RFC1195, you will see that external routes are only allowed to be originated by L2 routers. That is the standard. However, Cisco *does"* allow the use of TLV 130 (IP External Reachability Information TLV) in L1 LSPs. And it is from that that your confusion arises. Note that the above only applies when using narrow metrics.
>
> When using wide metrics, the only TLV used is TLV 135 (The Extended IP Reachability TLV) - check out RFC3784. This TLV has no concept of internal or external, which explains the results you see.
>
> HTH,
> Paresh.
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of Dillon Yang
> Sent: Thursday, 14 July 2005 12:57 AM
> To: Group Study
> Subject: Doyle's comment vs ISIS external route
>
>
> Hi, group:
>
> I am finding a way to distinguish ISIS internal or external route, but I found something strange:
>
> [Question01]
>
>
> Whereas L2 routes may be either internal or external, L1 routes are always internal.
>
> You see, under L1-only routing, the router is generating the "IP-External" routes, and the routes was in the routing table.
> How can you explain this problem, if you were Mr. Doyle?
>
> [config01]
> !
> interface Loopback11
> ip address 11.6.6.1 255.255.255.0
> !
> interface Loopback12
> ip address 11.6.7.1 255.255.255.0
> !
> interface Loopback13
> ip address 11.6.8.1 255.255.255.0
> !
> interface Loopback14
> ip address 11.6.9.1 255.255.255.0
> !
> interface Loopback211
> ip address 211.211.211.1 255.255.255.0
> ip router isis fr
> !
> interface Ethernet0
> ip address 150.100.2.254 255.255.255.0
> ip router isis fr
> no ip route-cache
> no ip mroute-cache
> clns router isis fr
> !
> !
> router isis fr
> net 49.0001.9999.9999.9999.00
> redistribute connected metric-type external level-1
> is-type level-1
> !
> end
>
> R6#s isis dat det
>
> IS-IS Level-1 Link State Database:
> LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
> R4.00-00 0x00000015 0xFF15 626 1/0/0
> Area Address: 49.0001
> NLPID: 0x81 0xCC
> Hostname: R4
> IP Address: 150.100.2.3
> Metric: 10 IP 150.100.2.0 255.255.255.0
> Metric: 10 IS R6.02
> Metric: 0 ES R4
> R6.00-00 * 0x00000015 0xFA76 642 0/0/0
> Area Address: 49.0001
> NLPID: 0x81 0xCC
> Hostname: R6
> IP Address: 211.211.211.1
> Metric: 10 IP 150.100.2.0 255.255.255.0
> Metric: 10 IP 211.211.211.0 255.255.255.0
> Metric: 10 IS R6.02
> Metric: 0 ES R6
> Metric: 64 IP-External 11.6.9.0 255.255.255.0
> Metric: 64 IP-External 11.6.8.0 255.255.255.0
> Metric: 64 IP-External 11.6.7.0 255.255.255.0
> Metric: 64 IP-External 11.6.6.0 255.255.255.0
> R6.02-00 * 0x00000012 0xC7B1 677 0/0/0
> Metric: 0 IS R6.00
> Metric: 0 IS R4.00
> R6#
>
> [Question02]
>
> The more strange thing followed, when I added the command "metric-style wide", the router did not generate the "IP-External" routes and these routes did not appear in the routing table.
> How can it works?
>
> [config02]
>
> R6#conf t
> Enter configuration commands, one per line. End with CNTL/Z.
> R6(config)#router isis fr
> R6(config-router)#metric
> R6(config-router)#metric-style wi level-1
> R6(config-router)#end
> R6.00-00 * 0x00000007 0x951B 1187 1/0/0
> Area Address: 01
> NLPID: 0xCC
> Hostname: R6
> IP Address: 211.211.211.1
> Metric: 10 IP 211.211.211.0/24
> Metric: 10 IP 3.3.16.0/24
> Metric: 10 IS-Extended R1.00
> Metric: 0 IP 11.6.9.0/24
> Metric: 0 IP 11.6.8.0/24
> Metric: 0 IP 11.6.7.0/24
> Metric: 0 IP 11.6.6.0/24
>
> routing table:
>
> C 211.211.211.0/24 is directly connected, Loopback211
> 3.0.0.0/24 is subnetted, 16 subnets
> i L1 3.3.10.0 [115/74] via 3.3.16.1, Serial0.601, fr
> i L1 3.3.13.0 [115/30] via 3.3.16.1, Serial0.601, fr
> i L1 3.3.14.0 [115/30] via 3.3.16.1, Serial0.601, fr
>
>
> TIA
> dillon
>
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