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ospf dr

rpalacio
Level 1
Level 1

Our clients 6500 is configured on vlans and is running ospf with area 10, stub.

(vlan10--vlan20--vlan30)-----(2620router)----(remotes

From the setup above;

1. vlan 30 is connected to the router.

2. router is connected to the remotes.

3. all vlans are configured ospf priority ZERO.

servers are connected to vlan 30.

question;

1. DR appears only on the vlan30. Is it just okay? okay.

2. network login is slow on users on vlan 10 and 20 compared to users on vlan 30 which are on the same subnet as the servers. Does it have to do something on the vlans not having DR/BDR?

11 Replies 11

Harold Ritter
Cisco Employee
Cisco Employee

You should definitely have one DR per subnet. Failure do that will prevent any adjadency on that subnet. I would certainly advise to remove the priority 0 as it cause the router not to become a DR on that segment. I don't why you even have connectivity at the moment, perhaps because of static routes but you should should definitely solve the DR issue.

Hope this helps,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

When two routers attached to a network both attempt to become the designated router, the one with the higher router priority takes precedence. If there is a tie, the router with the higher router ID takes precedence. A router with a router priority set to zero is ineligible to become the designated router or backup designated router.

the problem in this case is a missing second router with "ospf priority" > 0

all networks are directly connected.

kind regards Peter

You are correct. Vlan 10, 20 and 30 are not transit networks. so it doesn't matter if there is a DR or not. You could even configure these subinterfaces as passive.

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

the problem in this case is a missing second router with "ospf priority" > 0....

the router 2620xm was having the default ospf priority...thats why vlan3 has taken it as a DR...my only problem is that vlan 1 and 2 doesnt have any DR...I know that they will not participate in the election of DR/BDR due to their ospf priority set to 0, but they should be able to obtain their respective DR/BDR..I just dont know why they are not having 1.

does exist a second router with ospf priority >0 on Vlan10 or 20?

If not everything is fine

as per my diagram, the router is connected to vlan30

I am just avoiding additional load on the 6500 core thats why i put the ospf priority to zero...

DOesnt it mean that the vlans do not participate in the DR/BDR election but should obtain one?

This is happening only on my vlan30..It has taken the 2620 as the DR...Note that vlan 30 does also have a ospf priority of zero.

pswarovsky
Level 1
Level 1

1. If no other router is connected to VLAN 10 and 20 this is OK.

2. As I understand your topology, clients connected to VLAN 30 don't need a router to connect at your server because they are at the same subnet.

Users connected to VLAN 10/20 must be routed over your 2620, you reach more delay.

I think DR isn't the Problem

Which default-gateway is configured on your clients and where is this IP-address located?

Why do you not configure Inter-VLAN routing on the 6500?

kind regards Peter

hellooo....intervlan is configured on 6500...thats why iam saying it is running ospf...my problem is that vlan 10 and 20 is not having any DR/BDR..only vlan30 is having one...is this normal?...isnt this is the one causing vlan 10 and 20 to go slower in logging in to the domain server which is on vlan 30?

users on vlan 30 doesnt have this problem.

sorry but I'm a little bit confused.

Is it possible for you to past ospf and interface configuration from all Routers/Interfaces connected to VLAN 10/20/30

to this forum or just send me an email.

kind regards Peter

ok, ill try my best to do that. just giv me some time.

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