02-12-2019 09:42 AM - edited 03-05-2019 11:16 AM
Hello experts,
I know this is the topic which discusses with a lot of thread, but I took a look and can't found any perfect solution. the classic topology below
===ISP A AS 101=== ===ISP B AS 102===
| |
AS100_rtrA AS100_rtrB
| |
===Company class C IP address AS100===
Company direction using BGP with receiving default route and advertise a standard class C, also with IPSLA to change the HSRP for the failover if the main link (RTR A) goes wrong. we all understand that is just able to influence the outbound but not inbound traffic.
But now, I want to provide a better failover by
1) putting a peer link in between to provide additional failover layer. also
2) base on IP SLA if the link quality goes wrong,(e.g ping lost) then I can swing both i/o bound traffic to rtr_b
===ISP A AS 101=== ===ISP B AS 102===
| |
AS100_rtrA--------------AS100_rtrB
| |
===Company class C IP address AS100===
I read a lot of failover post, but some people doing in a "low-tech" way by using EEM to "type" additional command in CLI (like shutdown BGP instance in the router with problem ISP uplink), also some BGP guru has a lot BGP config in "high-tech", way --but those cant change based on the actual link quality.
Question
Is that any way that I can adjust local preference and AS prepend by based on IP SLA?
02-12-2019 09:55 AM
perkin,
I think a better solution would be to use floating static route on primary router that would depend on IP SLA probe. If the link gone down, the route would disappear and router would stop advertising it altogether via BGP. Coupled with the same SLA controlling the HSRP failover, you would end up with a very neat and consistent failover scenario.
02-12-2019 11:00 AM
02-12-2019 09:55 AM
Hello,
basically, you can configure the IP SLA to monitor jitter/delay/packet loss and have an EEM script change the local preference based on the status of the IP SLA. That would be the simplest way to accomplish this.
That said, you also might want to have a look at PfR (Perforrmance Routing)...
02-13-2019 01:53 AM
thanks Georg,
thanks for your link for performance routing, I did read and google before my response. It seems to me that is more required both sides has PFR configured, it seems that may not very fit for my internet edge design.
but that is quite useful for my next internal design :-)
so in short, I may need to do the "cli" way with EEM :-)
02-13-2019 05:45 AM
02-13-2019 06:37 AM
02-13-2019 07:02 AM
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