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common ospf practice fpr a core switch

if i have a core switch participating in an ospf process with quite a few number of routers in an area (say 20 routers on a frame relay), is it a common practice to allow the core switch to be a dr or a bdr?

i have configured the core to have an ospf priority of zero for it not to participate in the dr/bdr election..Am I on the right track?

thanks a lot.

4 REPLIES
VIP Purple

Re: common ospf practice fpr a core switch

Hello,

it depends on the setup of your network. Since you say that you are using 20 routers connected with Frame Relay, I assume that this is a hub-and-spoke network ? In this case, the hub router should be the DR, also because it usually has the most CPU power and memory. That means that your core switch can have a priority of 0 and never be a DR or BDR. What is the function of the core switch in your network ?

Regards,

Georg

New Member

Re: common ospf practice fpr a core switch

ill try to give you a picture of the network

20 remotes----main router---core(L3)---IR---L3_ABR

FROM THE FIGURE

1. main router to 20 routers form the hub and spoke.

2. core switch is vlan configured. core switch is connected to another L3 (L3_ABR) thru infrared (IR)

3. L3_ABR is the switch connecting to area zero thru infrared, with some backup link such as mpls and another infrared thru other routes. It was vlan configured too.

VIP Purple

Re: common ospf practice fpr a core switch

Hello,

in that case I would let the core L3 switch be the BDR. An infrared link to me sounds like it could be more vulnerable to a failure than your core switch, which is probably directly physically connected to yuor main router.

Regards,

Georg

New Member

Re: common ospf practice fpr a core switch

in this case, the ABR is the L3_ABR..Theoriticaly, it is said that the ABR will forward a default gateway.

1. Does it mean that my core switch default gateway will will depend on that.

2. Is the default gateway forwarded by the ABR meant for the hub router and the remote routers too. Or is it meant for the directly connected only (in this case the core switch)?

thank again for the help.

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