06-30-2021 06:27 AM
Hi,
I'm configuring IP SLA in Cisco Router to ping 8.8.8.8 , any idea how to specify the ip next hope?
Thank you
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06-30-2021 10:34 PM - edited 07-01-2021 05:25 AM
Hello
if i understand you wish to make sure ip sla icmp probe to 8.8.8.8 is only reachable via a certain default path possibly the active default path and negate the probe reaching 8,8,8.8 via an alternate path if/when the current default path becomes unavailable?
example1:
ip sla 1
icmp-echo 8.8.8.8 source-interface fa0/1
timeout 1000
threshold 2000
frequency 15
ip sla schedule 1 start now life forever
track 10 rtr1 reachabilty
ip route 0.0.0.0 0.0.0.0 fa0/1 x.x.x.x track10 name primary link
ip route 0.0.0.0 0.0.0.0 fa0/0 x.x.x.x 2 name backup link
ip route 8.8.8.8 255.255.255.255 Null0 2
example2:
same ip sla as in example 1
access-list 100 permit icmp host <source ip> host 8.8.8.8 echo
route-map ipsla
match ip address 100
set ip next-hop (next hop of interface fa0/1)
set interface Null0
ip local policy route-map ipsla
ip route 0.0.0.0 0.0.0.0 fa0/1 <nexthop ip> track 10 name primary link
ip route 0.0.0.0 0.0.0.0 fa0/0 <nexthop ip> 2 name backup link
06-30-2021 06:33 AM
I am may interpreting wrong here ? what are you looking for next hop syntax ?
example :
06-30-2021 07:04 AM
I'm looking to know if there is a way to specify which output interface to take.
I see in your example that route-map is used
06-30-2021 08:52 AM
Sure if you have different path to go out, yes you need to choose which path to choose to reach destination and based on the results take action.
06-30-2021 09:07 AM
but my question if how to do it , there is No "ip next hop" command in ip sla .
so what I did is : I added a route to 8.8.8.8/32 to go through a specific interface
06-30-2021 10:52 AM
Your next hop is determined by the routing table.
For example if to get to 8.8.8.8 you exit through Gi0/0/0 at IP address 192.168.1.1/24 (this ip configured on Gi0/0/0):
R1#show ip route 8.8.8.8
Routing entry for 8.8.8.8/32
Last update from 192.168.1.2 on GigabitEthernet0/0/0, 00:17:00 ago
If you work with static routing you can specify the route and the alternate interface through which the next hop should be found:
ip route 0.0.0.0 0.0.0.0 Gi0/0/0
06-30-2021 10:34 PM - edited 07-01-2021 05:25 AM
Hello
if i understand you wish to make sure ip sla icmp probe to 8.8.8.8 is only reachable via a certain default path possibly the active default path and negate the probe reaching 8,8,8.8 via an alternate path if/when the current default path becomes unavailable?
example1:
ip sla 1
icmp-echo 8.8.8.8 source-interface fa0/1
timeout 1000
threshold 2000
frequency 15
ip sla schedule 1 start now life forever
track 10 rtr1 reachabilty
ip route 0.0.0.0 0.0.0.0 fa0/1 x.x.x.x track10 name primary link
ip route 0.0.0.0 0.0.0.0 fa0/0 x.x.x.x 2 name backup link
ip route 8.8.8.8 255.255.255.255 Null0 2
example2:
same ip sla as in example 1
access-list 100 permit icmp host <source ip> host 8.8.8.8 echo
route-map ipsla
match ip address 100
set ip next-hop (next hop of interface fa0/1)
set interface Null0
ip local policy route-map ipsla
ip route 0.0.0.0 0.0.0.0 fa0/1 <nexthop ip> track 10 name primary link
ip route 0.0.0.0 0.0.0.0 fa0/0 <nexthop ip> 2 name backup link
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