12-31-2018 12:56 PM
I have two providers and in which all my incoming traffic is somewhat balanced using route maps, currently all outgoing traffic just goes to one provider and if that provider goes down then it rolls to the other. Is there a way I can force an individual IP address or range to go out my other provider while both are active?
12-31-2018 01:19 PM
Hello,
without knowing your exact topology, the easiest way to accomplish this is probably policy routing. You match an IP address, or a range, and then set the next hop or the outgoing interface that matches your respective ISP link..
12-31-2018 01:46 PM
I have tried
ip route X.X.X.X 255.255.255.255 Y.Y.Y.Y (isp B) but this kills the IP address all together.
The only thing I can come up with is setting up a route-map with a local preference that includes the ip address or range and set it to the neighbor ... I haven't tried this yet as I was hoping there is a simpler solution.
12-31-2018 01:48 PM
Hello,
what does your topology look like ? Since you are using local preference I assume you have at least two routers ?
12-31-2018 01:50 PM
Single ASR Router - Multi homed with ISP A and ISP B
12-31-2018 01:52 PM
12-31-2018 02:41 PM
01-02-2019 05:34 AM
If I accept full routes or only a default route from each provider will I be able to use local pref in a route map for different subnets?
12-31-2018 01:52 PM
Hello,
policy routing is definitely an option then. Can you post the config of your ASR ?
12-31-2018 01:56 PM
Its a pretty large config I would rather not post the entire thing on here, is there something specific you would like to see from it?
12-31-2018 02:03 PM
Hello,
for the policy routing I basically only need to see the LAN as well as both ISP facing interfaces...
01-02-2019 05:40 AM
interface TenGigabitEthernet0/3/0
description ISP B 10GB
ip address Y.Y.Y.50 255.255.255.252
no ip redirects
no ip proxy-arp
ip nat outside
ip flow monitor ddosB input
ip access-group 136 in
ip access-group 128 out
ipv6 address YYYY
ipv6 enable
ipv6 traffic-filter all_network in
ipv6 traffic-filter all_network out
nat64 enable
interface TenGigabitEthernet1/3/0
description Connected to ISP A 10GB
ip address X.X.X.190 255.255.255.252
no ip redirects
no ip proxy-arp
ip nat outside
ip flow monitor ddos input
ip access-group 136 in
ip access-group 128 out
ipv6 address XXXX
ipv6 enable
nat64 enable
neighbor X.X.X.189 route-map ISPA out
neighbor X.X.X.189 filter-list 3 out
neighbor Y.Y.Y.49 send-community
neighbor Y.Y.Y.49 route-map ISPB out
neighbor Y.Y.Y.49 filter-list 3 out
Does this have what you are looking for?
12-31-2018 02:44 PM - edited 12-31-2018 02:44 PM
As suggested by Georg, a PBR would be the easiest way to do it :
https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/10116-36.html
As you are using multi homed providers, you might also be interested on the verify-availability feature for PBR for fallback next hops.
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_pi/command/iri-cr-book/iri-cr-s1.html#wp8093935770
01-01-2019 05:00 AM
If you are receiving full routes from one ISP and only a default route from the other ISP then neither local preference nor weight will be effective. Either you need to have multiple routes from both ISP or you need PBR.
HTH
Rick
01-02-2019 06:01 AM - edited 01-02-2019 06:14 AM
Hello
@Brandon Baker wrote:
I have two providers and in which all my incoming traffic is somewhat balanced using route maps, currently all outgoing traffic just goes to one provider and if that provider goes down then it rolls to the other. Is there a way I can force an individual IP address or range to go out my other provider while both are active?
Single ASR Router - Multi homed with ISP A and ISP B
You can LB on received routes using BGP Weight PA which isn't as specific as PBR but very useful.
Example:
access-list 10 permit 123.123.123.0 0.0.0.255
route-map ISP1-Weight permit 10
set weight 30000
route-map ISP2-Weight permit 10
match ip address 10
set weight 40000
route-map ISP2-Weight permit 99
set weight 20000
router bgp x
neighbor x.x.x route-map ISP1-Weight in
neighbor x.x.x route-map ISP2-Weight in
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