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syadnom
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set OSPF cost on SSTP/PPTP?

Tue Jul 31, 2012 5:12 am

I am looking for a way to automatically set OSPF cost on PPP type connections like SSTP and PPTP.

The situation I have is that I have 2 WAN interfaces on my core.

I have router1 on wan1 and router2 on wan2, then an ethernet cable between router1 and router2 and a /29 connecting them and they are in the OSPF area. router1 is the primary, and wan1 is the primary (with router2 and wan2 being the backup/redundants)

I have a tunnel from each remote site to wan1/router1 and wan2/router2. OSPF is handling this perfectly, the extra hop between router1 and router2 makes the in and outbound shortest route via wan1/router1.

Here is the problem/annoyance. Site1 has a tunnel to router1 and router2. Site2 has a tunnel to router1 and router2. That means that there are two ECMP hops from Site1 to Site2. Site1<>Router1<>Site2 and Site1<>Router2<>Site2. So now site1<>site2 packets are going to send round-robin style to both Router1/wan1 and Router2/wan2. Wan1 and Wan2 are from different providers and have different latencies. Also, WAN2 does some web serving and is truly meant as a backup circuit.

If I could just make the cost for these dynamic interfaces higher it would solve the problem, but I can't find a way to do it. They show up in my OSPF interfaces list as cost 10 and nothing I try changes that. Just moving them to cost 11 would do it. Site1<>Router1<>Site2 is cost=20, while Site1<>Router2<>Site2 would be cost=22.

Thanks in advance
 
physon
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Re: set OSPF cost on SSTP/PPTP?

Mon Aug 06, 2012 8:01 pm

You can increase the default cost by adding an "all" ospf interface and setting the cost on that.

But really it's probably easier and cleaner to lower the costs of the other non-dynamic interfaces if you can.
 
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hassibi
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Re: set OSPF cost on SSTP/PPTP?

Mon Aug 06, 2012 9:30 pm

Hi
i think if you want to change cost of a few PPP link you can add dedicated server interface for each user you want and then you can change their OSPF interfaces costs.
 
syadnom
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Re: set OSPF cost on SSTP/PPTP?

Tue Aug 07, 2012 6:35 am

You can increase the default cost by adding an "all" ospf interface and setting the cost on that.

But really it's probably easier and cleaner to lower the costs of the other non-dynamic interfaces if you can.
that did the trick. I was overthinking it, looking at instances and everywhere else. I setup an all entry and it works as desired.

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