Setting routes w/ set next hop verify-availability in IOS 12.2

Discussion in 'Cisco' started by ttripp, Feb 11, 2009.

  1. ttripp

    ttripp Guest

    I'm trying to set up a 6509 switch with a MSFC2 card to route based on
    the reachability of one of two outbound routers. I've set up this
    sort of thing using:

    ip sla monitor 1
    type echo protocol ipicmpEcho 10.100.20.5
    frequency 15

    ip sla schedule 1 start-time now life forever

    track 1 rtr 1 reachability

    ip route x.x.x.x 255.255.255.255 10.100.20.5 track 1

    on routers that have IOS 12.3 or later. What I'm doing is monitoring
    10.100.20.5 with pings, and if the pings work, I'm adding a static
    route for a particular host pointing to 10.100.20.5. If the ping
    fails, then the static route is remove and the host uses whatever
    entry is in the routing table. I've used this approach before
    successfully.

    Unfortunately, the version of IOS available for the MSFC2 tops out at
    12.2, so I can't use this particular solution.

    I've come across an older tracking method that is compatible with
    12.2, but I'm not sure about its behavior. This is what I've found:

    track 123 rtr 1 reachability

    interface vlan0
    ip address 10.100.30.1 255.255.255.0
    ip policy route-map alpha

    route-map alpha permit 10
    match ip address "ACL-Including-x,x,x,x"
    set ip next-hop verify-availability 10.100.20.5 10 track 123

    rtr 1
    type echo protocol ipIcmpEcho 10.100.20.5
    rtr schedule 1 life forever start-time now

    I think that will do what I want, setting the next hop for that
    particular host if there is a good ping to that specific outbound
    router. What I'm not clear on is, what happens if the ping fails?
    Will the host then just use whatever route is in the MSFC2's routing
    table, or will it not have any route at all and the packets from the
    host just drop?

    Thanks in advance.
     
    ttripp, Feb 11, 2009
    #1
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  2. ttripp

    Thrill5 Guest

    "ttripp" <> wrote in message
    news:...
    > I'm trying to set up a 6509 switch with a MSFC2 card to route based on
    > the reachability of one of two outbound routers. I've set up this
    > sort of thing using:
    >
    > ip sla monitor 1
    > type echo protocol ipicmpEcho 10.100.20.5
    > frequency 15
    >
    > ip sla schedule 1 start-time now life forever
    >
    > track 1 rtr 1 reachability
    >
    > ip route x.x.x.x 255.255.255.255 10.100.20.5 track 1
    >
    > on routers that have IOS 12.3 or later. What I'm doing is monitoring
    > 10.100.20.5 with pings, and if the pings work, I'm adding a static
    > route for a particular host pointing to 10.100.20.5. If the ping
    > fails, then the static route is remove and the host uses whatever
    > entry is in the routing table. I've used this approach before
    > successfully.
    >
    > Unfortunately, the version of IOS available for the MSFC2 tops out at
    > 12.2, so I can't use this particular solution.
    >
    > I've come across an older tracking method that is compatible with
    > 12.2, but I'm not sure about its behavior. This is what I've found:
    >
    > track 123 rtr 1 reachability
    >
    > interface vlan0
    > ip address 10.100.30.1 255.255.255.0
    > ip policy route-map alpha
    >
    > route-map alpha permit 10
    > match ip address "ACL-Including-x,x,x,x"
    > set ip next-hop verify-availability 10.100.20.5 10 track 123
    >
    > rtr 1
    > type echo protocol ipIcmpEcho 10.100.20.5
    > rtr schedule 1 life forever start-time now
    >
    > I think that will do what I want, setting the next hop for that
    > particular host if there is a good ping to that specific outbound
    > router. What I'm not clear on is, what happens if the ping fails?
    > Will the host then just use whatever route is in the MSFC2's routing
    > table, or will it not have any route at all and the packets from the
    > host just drop?
    >
    > Thanks in advance.


    The route map will override the normal routing for that subnet. If the sla
    monitor says that the router is available then it set the next-hop to
    10.100.20.5, otherwise it will send it to where the routing table says it
    should go. I'm curious as to what you are trying to accomplish. Why aren't
    you running a routing protocol on 10.100.20.5 or just using a static or
    floating-static route?
     
    Thrill5, Feb 11, 2009
    #2
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  3. ttripp

    ttripp Guest

    On Feb 11, 5:49 pm, "Thrill5" <> wrote:
    > "ttripp" <> wrote in message
    >
    > news:...
    >
    >
    >
    >
    >
    > > I'm trying to set up a 6509 switch with a MSFC2 card to route based on
    > > the reachability of one of two outbound routers.  I've set up this
    > > sort of thing using:

    >
    > >     ip sla monitor 1
    > >      type echo protocol ipicmpEcho 10.100.20.5
    > >      frequency 15

    >
    > >     ip sla schedule 1 start-time now life forever

    >
    > >     track 1 rtr 1 reachability

    >
    > >     ip route x.x.x.x 255.255.255.255 10.100.20.5 track 1

    >
    > > on routers that have IOS 12.3 or later.  What I'm doing is monitoring
    > > 10.100.20.5 with pings, and if the pings work, I'm adding a static
    > > route for a particular host pointing to 10.100.20.5.  If the ping
    > > fails, then the static route is remove and the host uses whatever
    > > entry is in the routing table.  I've used this approach before
    > > successfully.

    >
    > > Unfortunately, the version of IOS available for the MSFC2 tops out at
    > > 12.2, so I can't use this particular solution.

    >
    > > I've come across an older tracking method that is compatible with
    > > 12.2, but I'm not sure about its behavior.  This is what I've found:

    >
    > >     track 123 rtr 1 reachability

    >
    > >     interface vlan0
    > >      ip address 10.100.30.1 255.255.255.0
    > >      ip policy route-map alpha

    >
    > >     route-map alpha permit 10
    > >      match ip address "ACL-Including-x,x,x,x"
    > >      set ip next-hop verify-availability 10.100.20.5 10 track 123

    >
    > >     rtr 1
    > >      type echo protocol ipIcmpEcho 10.100.20.5
    > >      rtr schedule 1 life forever start-time now

    >
    > > I think that will do what I want, setting the next hop for that
    > > particular host if there is a good ping to that specific outbound
    > > router.  What I'm not clear on is, what happens if the ping fails?
    > > Will the host then just use whatever route is in the MSFC2's routing
    > > table, or will it not have any route at all and the packets from the
    > > host just drop?

    >
    > > Thanks in advance.

    >
    > The route map will override the normal routing for that subnet.  If the sla
    > monitor says that the router is available then it set the next-hop to
    > 10.100.20.5, otherwise it will send it to where the routing table says it
    > should go.  I'm curious as to what you are trying to accomplish.  Why aren't
    > you running a routing protocol on 10.100.20.5 or just using a static or
    > floating-static route?- Hide quoted text -
    >
    > - Show quoted text -


    I'm trying to load-balance voice/video traffic across multiple MPLS
    connections and 7200 routers running OSPF without getting into BGP.
    Using sla will let me point specific videoconferencing units out
    specific routers, while letting those same units fail over to using
    the OSPF routing table if a specific MPLS connection goes down. It's
    a bit convoluted, but BGP would be even more convoluted.

    Of course, if you've got a better solution, I'd sure like to hear it.
     
    ttripp, Feb 12, 2009
    #3
  4. ttripp

    Uli Link Guest

    ttripp schrieb:

    > I'm trying to load-balance voice/video traffic across multiple MPLS
    > connections and 7200 routers running OSPF without getting into BGP.
    > Using sla will let me point specific videoconferencing units out
    > specific routers, while letting those same units fail over to using
    > the OSPF routing table if a specific MPLS connection goes down. It's
    > a bit convoluted, but BGP would be even more convoluted.
    >
    > Of course, if you've got a better solution, I'd sure like to hear it.


    Just as Thriil5 wrote:

    A floating static route with object tracking and a metric lower than the
    OSPF metric. The solution is described for firing up and down a
    dial-backup, but it's a generic trick.

    You can do this with route-map too, but in a more
    shoot-yourself-in-the-foot manner.

    --
    ULi
     
    Uli Link, Feb 12, 2009
    #4
  5. ttripp

    ttripp Guest

    On Feb 12, 8:49 am, Uli Link <> wrote:
    > ttripp schrieb:
    >
    > > I'm trying to load-balance voice/video traffic across multiple MPLS
    > > connections and 7200 routers running OSPF without getting into BGP.
    > > Using sla will let me point specific videoconferencing units out
    > > specific routers, while letting those same units fail over to using
    > > the OSPF routing table if a specific MPLS connection goes down.  It's
    > > a bit convoluted, but BGP would be even more convoluted.

    >
    > > Of course, if you've got a better solution, I'd sure like to hear it.

    > Just as Thriil5 wrote:
    >
    > A floating static route with object tracking and a metric lower than the
    > OSPF metric. The solution is described for firing up and down a
    > dial-backup, but it's a generic trick.
    >
    > You can do this with route-map too, but in a more
    > shoot-yourself-in-the-foot manner.
    >
    > --
    > ULi


    Well, that brings me back to the original post. Is that sort of
    tracking available in 12.2? I don't just want to track the interface
    on the local router (or routing switch, in this case), but out across
    my MPLS network.
     
    ttripp, Feb 12, 2009
    #5
  6. ttripp

    Thrill5 Guest

    "ttripp" <> wrote in message
    news:...
    On Feb 12, 8:49 am, Uli Link <> wrote:
    > ttripp schrieb:
    >
    > > I'm trying to load-balance voice/video traffic across multiple MPLS
    > > connections and 7200 routers running OSPF without getting into BGP.
    > > Using sla will let me point specific videoconferencing units out
    > > specific routers, while letting those same units fail over to using
    > > the OSPF routing table if a specific MPLS connection goes down. It's
    > > a bit convoluted, but BGP would be even more convoluted.

    >
    > > Of course, if you've got a better solution, I'd sure like to hear it.

    > Just as Thriil5 wrote:
    >
    > A floating static route with object tracking and a metric lower than the
    > OSPF metric. The solution is described for firing up and down a
    > dial-backup, but it's a generic trick.
    >
    > You can do this with route-map too, but in a more
    > shoot-yourself-in-the-foot manner.
    >
    > --
    > ULi


    Well, that brings me back to the original post. Is that sort of
    tracking available in 12.2? I don't just want to track the interface
    on the local router (or routing switch, in this case), but out across
    my MPLS network.

    Doing this with BGP would be much easier. You could redistribute the
    desired routes into OSPF, using a route-map. The route-map is used to
    specify which routes would get redistributed into OSPF. I'm sure there
    are other simpler solutions to your problem, but without more details it's
    hard to tell you what they are. The solution you have come up with is very
    complicated, and like killing a fly with a sledge hammer.
     
    Thrill5, Feb 13, 2009
    #6
  7. ttripp

    Uli Link Guest

    ttripp schrieb:
    >
    > Well, that brings me back to the original post. Is that sort of
    > tracking available in 12.2? I don't just want to track the interface
    > on the local router (or routing switch, in this case), but out across
    > my MPLS network.


    nope.

    12.3T or better use 12.4 mainline.

    --
    ULi
     
    Uli Link, Feb 14, 2009
    #7
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