I could not find any definitive description either. I have tried used RID
and also physical but only RID has any effect. I have also used with and
without an acl on the distance command.
Here are some interesting captures from my testing showing the distance
command behaviour:
Cat2(config)#do sh run | s ospf
router ospf 1
network 136.10.56.0 0.0.0.15 area 3
distance 109 136.10.5.5 0.0.0.0
Cat2(config)#
#### show ip route ospf shows equal cost routes with default AD due to
being sourced from R6, except for directly connected R5 sourced routes
####
Cat2(config)#do sh ip route ospf
136.10.0.0/16 is variably subnetted, 15 subnets, 4 masks
O IA 136.10.6.6/32 [110/2] via 136.10.56.6, 00:08:14, Vlan56
*O IA 136.10.5.5/32 [109/2] via 136.10.56.5, 00:08:14, Vlan56*
O IA 136.10.4.4/32 [110/194] via 136.10.56.6, 00:08:14, Vlan56
[110/194] via 136.10.56.5, 00:08:14, Vlan56
*O IA 136.10.2.2/32 [110/130] via 136.10.56.6, 00:08:14, Vlan56*
* [110/130] via 136.10.56.5, 00:08:14, Vlan56*
O IA 136.10.24.0/24 [110/193] via 136.10.56.6, 00:08:14, Vlan56
[110/193] via 136.10.56.5, 00:08:14, Vlan56
O IA 136.10.40.0/24 [110/194] via 136.10.56.6, 00:08:14, Vlan56
[110/194] via 136.10.56.5, 00:08:14, Vlan56
O IA 136.10.100.6/32 [110/1] via 136.10.56.6, 00:08:14, Vlan56
O IA 136.10.100.5/32 [109/1] via 136.10.56.5, 00:08:14, Vlan56
O IA 136.10.100.2/32 [110/129] via 136.10.56.6, 00:08:14, Vlan56
[110/129] via 136.10.56.5, 00:08:14, Vlan56
Cat2(config)#do sh ip route 136.10.2.2
Routing entry for 136.10.2.2/32
Known via "ospf 1", *distance 110*, metric 130, type inter area
*Last update from* *136.10.56.6* on Vlan56, 00:08:28 ago
Routing Descriptor Blocks:
*136.10.56.6, from 136.10.6.6*, 00:08:28 ago, via Vlan56
Route metric is 130, traffic share count is 1
* *136.10.56.5, from 136.10.5.5*, 00:08:28 ago, via Vlan56
Route metric is 130, traffic share count is 1
##### In order to generate updated LSA, shut s1/0 on R5 ######
Cat2(config)#
03:07:56: RT: del 136.10.100.5/32 via 136.10.56.5, ospf metric [110/1]
03:07:56: RT: add 136.10.100.5/32 via 136.10.56.6, ospf metric [110/185]
03:07:56: RT: NET-RED 136.10.100.5/32
03:07:56: RT: del 136.10.2.2/32 via 136.10.56.5, ospf metric [110/130]
03:07:56: RT: NET-RED 136.10.2.2/32
03:07:56: RT: del 136.10.4.4/32 via 136.10.56.5, ospf metric [110/194]
03:07:56: RT: NET-RED 136.10.4.4/32
03:07:56: RT: del 136.10.100.2/32 via 136.10.56.5, ospf metric [110/129]
03:07:56: RT: NET-RED 136.10.100.2/32
03:07:56: RT: del 136.10.24.0/24 via 136.10.56.5, ospf metric [110/193]
03:07:56: RT: NET-RED 136.10.24.0/24
03:07:56: RT: del 136.10.40.0/24 via 136.10.56.5, ospf metric [110/194]
03:07:56: RT: NET-RED 136.10.40.0/24
03:08:17: RT: del 136.10.100.5/32 via 136.10.56.6, ospf metric [109/185]
03:08:17: RT: add 136.10.100.5/32 via 136.10.56.5, ospf metric [109/1]
03:08:17: RT: NET-RED 136.10.100.5/32
#### Equal cost route has been removed ####
Cat2(config)#do sh ip route ospf
136.10.0.0/16 is variably subnetted, 15 subnets, 4 masks
O IA 136.10.6.6/32 [110/2] via 136.10.56.6, 00:09:24, Vlan56
O IA 136.10.5.5/32 [109/2] via 136.10.56.5, 00:09:24, Vlan56
O IA 136.10.4.4/32 [110/194] via 136.10.56.6, 00:09:24, Vlan56
*O IA 136.10.2.2/32 [110/130] via 136.10.56.6, 00:09:24, Vlan56*
O IA 136.10.24.0/24 [110/193] via 136.10.56.6, 00:09:24, Vlan56
O IA 136.10.40.0/24 [110/194] via 136.10.56.6, 00:09:24, Vlan56
O IA 136.10.100.6/32 [110/1] via 136.10.56.6, 00:09:24, Vlan56
O IA 136.10.100.5/32 [109/1] via 136.10.56.5, 00:00:05, Vlan56
O IA 136.10.100.2/32 [110/129] via 136.10.56.6, 00:09:24, Vlan56
Cat2(config)#
#### No shut s1/0 on R5, new LSA is generated and routes are now sourced
from R5, equal paths installed and AD from distance command is applied to *both
*R5 and R6 routes. Routes sourced from R6 remain default AD 110. #######
Cat2(config)#
03:08:37: RT: add 136.10.100.2/32 via 136.10.56.5, ospf metric [109/129]
03:08:37: RT: NET-RED 136.10.100.2/32
03:08:37: RT: add 136.10.4.4/32 via 136.10.56.5, ospf metric [109/194]
03:08:37: RT: NET-RED 136.10.4.4/32
03:08:37: RT: add 136.10.2.2/32 via 136.10.56.5, ospf metric [109/130]
03:08:37: RT: NET-RED 136.10.2.2/32
03:08:37: RT: add 136.10.24.0/24 via 136.10.56.5, ospf metric [109/193]
03:08:37: RT: NET-RED 136.10.24.0/24
03:08:37: RT: add 136.10.40.0/24 via 136.10.56.5, ospf metric [109/194]
03:08:37: RT: NET-RED 136.10.40.0/24
Cat2(config)#
Cat2(config)#do sh ip route ospf
136.10.0.0/16 is variably subnetted, 15 subnets, 4 masks
*O IA 136.10.6.6/32 [110/2] via 136.10.56.6, 00:09:45, Vlan56*
O IA 136.10.5.5/32 [109/2] via 136.10.56.5, 00:09:45, Vlan56
O IA 136.10.4.4/32 [109/194] via 136.10.56.6, 00:09:45, Vlan56
[109/194] via 136.10.56.5, 00:00:07, Vlan56
*O IA 136.10.2.2/32 [109/130] via 136.10.56.6, 00:09:45, Vlan56*
* [109/130] via 136.10.56.5, 00:00:07, Vlan56*
O IA 136.10.24.0/24 [109/193] via 136.10.56.6, 00:09:45, Vlan56
[109/193] via 136.10.56.5, 00:00:07, Vlan56
O IA 136.10.40.0/24 [109/194] via 136.10.56.6, 00:09:45, Vlan56
[109/194] via 136.10.56.5, 00:00:07, Vlan56
O IA 136.10.100.6/32 [110/1] via 136.10.56.6, 00:09:45, Vlan56
O IA 136.10.100.5/32 [109/1] via 136.10.56.5, 00:00:27, Vlan56
O IA 136.10.100.2/32 [109/129] via 136.10.56.6, 00:09:45, Vlan56
[109/129] via 136.10.56.5, 00:00:07, Vlan56
Cat2(config)#do sh ip route 136.10.2.2
Routing entry for 136.10.2.2/32
Known via "ospf 1", *distance 109*, metric 130, type inter area
Last update from *136.10.56.5* on Vlan56, 00:00:16 ago
Routing Descriptor Blocks:
* *136.10.56.6, from 136.10.6.6*, 00:09:54 ago, via Vlan56
Route metric is 130, traffic share count is 1
*136.10.56.5, from 136.10.5.5,* 00:00:16 ago, via Vlan56
Route metric is 130, traffic share count is 1
Cat2(config)#
On Thu, Nov 17, 2011 at 2:35 PM, mark salmon <[email protected]> wrote:
> That is an interesting one. I believe I was able to match what the DSG
> said. What source IP address did you use? the RID or the physical IP
> address? I do not remember what I used. Interestingly I cannot find a good
> description on how to do it using the source IP address in the Docs.
>
>
>
> "Question with boldness even the existence of a God; because, if there be
> one, he must more approve of the homage of reason, than that of
> blind-folded fear." Thomas Jefferson
> " Where ignorance is bliss 'tis folly to be wise"
> ------------------------------
> *From:* James Roc <[email protected]>
> *To:* [email protected]
> *Sent:* Wednesday, November 16, 2011 9:51 PM
> *Subject:* [OSL | CCIE_RS] Vol2-Lab17-Task6.3 OSPF distance command to
> prefer equal path route
>
> Hi All,
>
> This task requires that "Cat2 will always prefer OSPF routes from R5"
> "without using the 'bandwidth' or 'ip ospf cost' commands."
> ____
> | |
> R5 R6
> |___|
> |
> CAT2
>
> The DSG uses the distance command to reduce R5 sourced routes to AD109.
>
> But as I understand, the 'distance' command cannot be used to select routes
> within the same routing protocol as OSPF makes the SPF decision THEN moves
> the route/s to the RIB. AD is then compared with other routing protocols or
> checked for infinite value 255.
>
> My testing shows that while the admin distance can be modified, both routes
> still remain in the RIB as equal paths. The AD of the router that sourced
> the route will be used for both equal path routes.
>
> Additionally, depending on who originated the last route update, the route
> source could be either R5 or R6.
>
> Below thread shows a similar issue but the question remains, given
> the constraints of the task and without actually filtering R6 routes or
> giving them a 255 admin distance, is it possible to prefer the routes from
> R5?
>
> Thanks
> James
>
>
> *Roger RPF* rpf at bluemail.ch
> <ccie_rs%
> 40onlinestudylist.com?Subject=Re%3A%20%5BOSL%20%7C%20CCIE_RS%5D%20Viol%202%20Section13%20Task%206.3%20OSPF%20distance&In-Reply-To=%3C001a01c9733e%24a9586940%24fc093bc0%24%40ch%3E
> >
> *Sat Jan 10 11:15:27 EST 2009*
>
>
> Hi Jared,
>
> Thanks, I got it.
>
> But the task says: "Cat2 will always prefer OSPF routes from R5"
>
> I know I am very bad in reading between the lines, furthermore I'm not
> native english, but how do I have to understand that? To me, this task
> means
> that for all OSPF routes he learns from R5 and R6, he will prefer R5.
> That's why I was confused...
>
> regards
> Roger
>
>
> -----Ursprüngliche Nachricht-----
> Von: Jared Scrivener [mailto:jscrivener at ipexpert.com
> <http://onlinestudylist.com/mailman/listinfo/ccie_rs>]
>
> Gesendet: Samstag, 10. Januar 2009 17:07
> An: 'Roger RPF'; ccie_rs at onlinestudylist.com
> <http://onlinestudylist.com/mailman/listinfo/ccie_rs>
>
> Betreff: RE: [OSL | CCIE_RS] Viol 2 Section13 Task 6.3 OSPF distance
>
> Roger,
>
> What you've described is EXACTLY how it should work. Quoting you:
>
> "To me, this means from what I have seen, that the command
> distance 109 <router-id>
> changes only the admin distance of the "local routes" of that particular
> router with that router-id, not ALL routes we are getting from it."
>
> This is the correct functionality. Remember that OSPF is a link-state
> protocol so each router advertises certain networks in its Type-1 (or
> Type-2) LSA's. What the distance command is doing is changing the distance
> for R5's Type 1 and Type 2 LSA's here.
>
> That is the expected behaviour.
>
> Cheers,
>
> Jared Scrivener CCIE3 #16983 (R&S, Security, SP), CISSP
> Technical Instructor - IPexpert, Inc.
> Telephone: +1.810.326.1444
> Fax: +1.810.454.0130
> Mailto: jscrivener at ipexpert.com
> <http://onlinestudylist.com/mailman/listinfo/ccie_rs>
>
>
>
> -----Original Message-----
> From: Roger RPF [mailto:rpf at bluemail.ch
> <http://onlinestudylist.com/mailman/listinfo/ccie_rs>]
> Sent: Saturday, 10 January 2009 5:51 AM
> To: jscrivener at ipexpert.com
> <http://onlinestudylist.com/mailman/listinfo/ccie_rs>; ccie_rs at
> onlinestudylist.com
> <http://onlinestudylist.com/mailman/listinfo/ccie_rs>
>
> Subject: AW: [OSL | CCIE_RS] Viol 2 Section13 Task 6.3 OSPF distance
>
> Hi Jared,
>
> Well, I tried it, cleared also the OSPF process but it dit not really help.
> Well, to be more specific, it made it worse than when I used the router-id,
> at least, the "local R5" routes got the better distance:
>
> O 136.10.5.5/32 [109/2] via 136.10.56.5, 1d03h, Vlan56
> O 136.10.25.0/30 [109/65] via 136.10.56.5, 1d03h, Vlan56
> O 136.10.100.5/32 [109/1] via 136.10.56.5, 1d03h, Vlan56
>
> but when I change the distance using the interface address, no route gets
> the better distance.
>
> To me, this means from what I have seen, that the command
> distance 109 <router-id>
> changes only the admin distance of the "local routes" of that particular
> router with that router-id, not ALL routes we are getting from it.
>
> But I think that is not how it SHOULD work, isn't it? Any ideas??
>
> regards
>
> Roger
>
>
> -----Ursprüngliche Nachricht-----
> Von: Jared Scrivener [mailto:jscrivener at ipexpert.com
> <http://onlinestudylist.com/mailman/listinfo/ccie_rs>]
>
> Gesendet: Samstag, 10. Januar 2009 02:59
> An: 'Roger RPF'; ccie_rs at onlinestudylist.com
> <http://onlinestudylist.com/mailman/listinfo/ccie_rs>
>
> Betreff: RE: [OSL | CCIE_RS] Viol 2 Section13 Task 6.3 OSPF distance
>
> Would you mind humouring me and trying:
>
> distance 109 136.10.56.5 0.0.0.0 2
>
> The OSPF distance command is meant to match based on router-id of the
> advertising router for the network. Yours *appears* to have matched by the
> network address instead.
>
> Let me know how that goes.
>
> Cheers,
>
> Jared Scrivener CCIE3 #16983 (R&S, Security, SP), CISSP
> Technical Instructor - IPexpert, Inc.
> Telephone: +1.810.326.1444
> Fax: +1.810.454.0130
> Mailto: jscrivener at ipexpert.com
> <http://onlinestudylist.com/mailman/listinfo/ccie_rs>
>
>
> -----Original Message-----
> From: Roger RPF [mailto:rpf at bluemail.ch
> <http://onlinestudylist.com/mailman/listinfo/ccie_rs>]
> Sent: Friday, 9 January 2009 2:19 AM
> To: jscrivener at ipexpert.com
> <http://onlinestudylist.com/mailman/listinfo/ccie_rs>; ccie_rs at
> onlinestudylist.com
> <http://onlinestudylist.com/mailman/listinfo/ccie_rs>
>
> Subject: AW: [OSL | CCIE_RS] Viol 2 Section13 Task 6.3 OSPF distance
>
> I cleared the OSPF process, but still the same issue...
>
> Any other ideas?
>
> -----Ursprüngliche Nachricht-----
> Von: Jared Scrivener [mailto:jscrivener at ipexpert.com
> <http://onlinestudylist.com/mailman/listinfo/ccie_rs>]
>
> Gesendet: Freitag, 9. Januar 2009 00:18
> An: 'Roger RPF'; ccie_rs at onlinestudylist.com
> <http://onlinestudylist.com/mailman/listinfo/ccie_rs>
>
> Betreff: RE: [OSL | CCIE_RS] Viol 2 Section13 Task 6.3 OSPF distance
>
> Did you set the router-id for OSPF on R5 to 136.10.5.5? The OSPF distance
> command should apply to the neighbor's router-id.
>
> Presuming that is correct, do a "clear ip ospf *" and see if that helps.
>
> Cheers,
>
> Jared Scrivener CCIE3 #16983 (R&S, Security, SP), CISSP
> Technical Instructor - IPexpert, Inc.
> Telephone: +1.810.326.1444
> Fax: +1.810.454.0130
> Mailto: jscrivener at ipexpert.com
> <http://onlinestudylist.com/mailman/listinfo/ccie_rs>
>
>
>
> -----Original Message-----
> From: ccie_rs-bounces at onlinestudylist.com
> <http://onlinestudylist.com/mailman/listinfo/ccie_rs>
> [mailto:ccie_rs-bounces at onlinestudylist.com
> <http://onlinestudylist.com/mailman/listinfo/ccie_rs>] On Behalf Of
>
> Roger RPF
> Sent: Thursday, 8 January 2009 4:21 PM
> To: ccie_rs at onlinestudylist.com
> <http://onlinestudylist.com/mailman/listinfo/ccie_rs>
>
> Subject: [OSL | CCIE_RS] Viol 2 Section13 Task 6.3 OSPF distance
>
> Hi group,
>
> I have a question regarding this task. One of them tells us that "Cat2 will
> always prefer OSPF routes from R5"
>
> the PG shows the solution
>
> router ospf 1
> distance 109 136.10.5.5 0.0.0.0 2
> access-list 2
> permit any
>
> But with this I will not see all OSPF routes preferred to R5. If I check my
> routing table (see partial output below), I only set this distance to the
> loopback of R5 (136.10.5.5) itself but for example for the routes to
> loopback of R4 (136.10.4.4) or R2 (136.10.2.2) or even the external RIP
> network from R2 (136.10.1.0), I still see both path over R5 and R6 and no
> one will be preferred through R5.
>
>
> O 136.10.5.5/32 [109/2] via 136.10.56.5, 00:00:20, Vlan56
> O 136.10.4.4/32 [110/130] via 136.10.56.6, 00:00:20, Vlan56
> [110/130] via 136.10.56.5, 00:00:20, Vlan56
> O 136.10.2.2/32 [110/66] via 136.10.56.6, 00:00:20, Vlan56
> [110/66] via 136.10.56.5, 00:00:20, Vlan56
> O E2 136.10.1.0/24 [110/20] via 136.10.56.6, 00:00:20, Vlan56
> [110/20] via 136.10.56.5, 00:00:21, Vlan56
>
> Do I understand something wrong??
>
> regards
>
> Roger
> _______________________________________________
> For more information regarding industry leading CCIE Lab training, please
> visit www.ipexpert.com
>
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>
>
>
_______________________________________________
For more information regarding industry leading CCIE Lab training, please visit
www.ipexpert.com
Are you a CCNP or CCIE and looking for a job? Check out
www.PlatinumPlacement.com
