[cisco-voip] weighted EIGRP routes

Thu Mar 18 11:00:09 EDT 2010

...it can be, but we're not using it as a layer three switch. we decided to do all the routing on the router to make it a simpler config. we'll end up saving money two since we don't have to buy the more expensive L3 switch and pay for ip services license for EIGRP. 

we'll try that out. thanks for the pointers. 

--- 
Lelio Fulgenzi, B.A. 
Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1 
(519) 824-4120 x56354 (519) 767-1060 FAX (JNHN) 
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 
Cooking with unix is easy. You just sed it and forget it. 
- LFJ (with apologies to Mr. Popeil) 

----- Original Message ----- 
From: "Brantley Richbourg" <Brantley.Richbourg at MMICNC.COM> 
To: "Lelio Fulgenzi" <lelio at uoguelph.ca> 
Cc: "Nate VanMaren" <VanMarenNP at ldschurch.org>, "cisco-voip voyp list" <cisco-voip at puck.nether.net> 
Sent: Thursday, March 18, 2010 10:57:58 AM GMT -05:00 US/Canada Eastern 
Subject: RE: [cisco-voip] weighted EIGRP routes 

It would need to be changed on the router's g2/0.201 interface where you are running EIGRP. I assume that your switch is not a layer 3 switch, right? 

From: Lelio Fulgenzi [mailto:lelio at uoguelph.ca] 
Sent: Thursday, March 18, 2010 10:43 AM 
To: Brantley Richbourg 
Cc: Nate VanMaren; cisco-voip voyp list 
Subject: Re: [cisco-voip] weighted EIGRP routes 

OK. In this case, the "interface" that connects the routers to the VG224 are not a physical interface, but a logical VLAN (or sub) interface. 

do I put the bandwidth/delay command on the gi2/0.201 sub-interface or on the switch's physical interface? 

on the router: 

interface gi2/0 
desc Service Module 
interface gi2/0.201 
encap dot1q 201 
ip address 192.168.201.1 /24 

on the internal switch: 

interface gi0/1 
vlan 201 
desc VG224 
interface gi0/18 
desc trunk to router 
allowed VLANs 201 (among others) 

on the vg224: 

interface fast0/0 
desc link to router 
ip address 192.168.201.2 /24 

--- 
Lelio Fulgenzi, B.A. 
Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1 
(519) 824-4120 x56354 (519) 767-1060 FAX (JNHN) 
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 
Cooking with unix is easy. You just sed it and forget it. 
- LFJ (with apologies to Mr. Popeil) 

----- Original Message ----- 
From: "Brantley Richbourg" <Brantley.Richbourg at MMICNC.COM> 
To: "Nate VanMaren" <VanMarenNP at ldschurch.org>, "Lelio Fulgenzi" <lelio at uoguelph.ca>, "cisco-voip voyp list" <cisco-voip at puck.nether.net> 
Sent: Thursday, March 18, 2010 10:33:02 AM GMT -05:00 US/Canada Eastern 
Subject: RE: [cisco-voip] weighted EIGRP routes 

If you want to change the metric calculations for an EIGRP route, you have to modify parameters that EIGRP uses to calculate the feasible distance. The bandwidth and delay commands on the interface(s) in question can accomplish this. You can verify by looking at the "show ip route" and you should see the next hop as the one for your primary path. "show ip eigrp topo" command will also show how feasible distance was calculated for each upstream router. 

If you change the bandwidth or delay on the interface that belongs to the upstream router, that will change the "Reported Distance" sent to the downstream router, which will in turn change the "weight" on that router to the upstream router. 

From: cisco-voip-bounces at puck.nether.net [cisco-voip-bounces at puck.nether.net] On Behalf Of Lelio Fulgenzi [lelio at uoguelph.ca] 
Sent: Wednesday, March 17, 2010 9:30 PM 
To: cisco-voip voyp list 
Subject: [cisco-voip] weighted EIGRP routes 

Any pointers on how to tell a downstream EIGRP neighbour to weigh one route better than another? Do I put the weight on the downstream neighbour to say EIGRP routes coming in on one interface should be weighted more heavily? Or on the upstream router to push down the weights? 

Basically, what I have is this: 

+-----------------------+ 
V V 
3945 -> switch -> VG224 <- switch <- 3945, where switch = SM-ESx-16 

(view with fixed font) 

Two 3945s with service module ethernet switches which connects to the two VG224 ports. All routing is done on the router and the switch provides layer two connectivity. A port channel group between the two switches allow the routers to communicate HSRP keepalives. The VG224 is an EIGRP stub, and the two upstream routers send out only default routes to the VG224 (that's all I want). 

Everything is working great. Except for the fact that the two upstream routers are equal weight. This means that when the VG224 is talking to the active HSRP address, it's going back and forth. Since the layer two link is up between the routers, it still works, but not ideal. Bad things happen if the link between the routers goes down - split brain! 

Any pointers? 

--- 
Lelio Fulgenzi, B.A. 
Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1 
(519) 824-4120 x56354 (519) 767-1060 FAX (JNHN) 
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 
Cooking with unix is easy. You just sed it and forget it. 
- LFJ (with apologies to Mr. Popeil) 

NOTICE: This email message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. 

Confidentiality: The information in this electronic mail may contain confidential, sensitive and/or protected health information intended only for the addressee(s). Any other person, including anyone who believes he/she might have received it due to an addressing error, is requested to notify this sender immediately by return e-mail, and shall delete it without further reading and retention. The information shall not be forwarded or shared unless in compliance with MMIC policies on confidentiality, and/or the written permission of this sender. 

Confidentiality: The information in this electronic mail may contain confidential, sensitive and/or protected health information intended only for the addressee(s). Any other person, including anyone who believes he/she might have received it due to an addressing error, is requested to notify this sender immediately by return e-mail, and shall delete it without further reading and retention. The information shall not be forwarded or shared unless in compliance with MMIC policies on confidentiality, and/or the written permission of this sender. 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://puck.nether.net/pipermail/cisco-voip/attachments/20100318/2563458b/attachment.html>