From: Brian Dennis (bdennis@internetworkexpert.com)
Date: Thu May 10 2007 - 16:04:29 ART
Is your S0/0 interface is a multipoint Frame Relay interface? If so here is
a post I made on this subject a few months ago.
With the static route pointing to the interface you are sending packets for
any destination out Serial0/0. If Serial0/0 is a point-to-point interface
then it will be sent to the remote end-point. This is because there can only
be one layer 3 to layer 2 mapping on a P2P interface and because of this all
packets use that layer 3 to layer 2 mapping.
If Serial0/0 is a multipoint interface (i.e. physical Frame Relay interface
or multipoint subinterface) then there can be more than one remote end-point
and hence more than one layer 3 to layer 2 mapping. In this case if the
static route points to the interface you have told the router that the
destination is directly connected to S0/0. But since the router does not
have a layer 3 to layer 2 mapping for the destination it in turn drops the
packet. To resolve this you can either configure the static route to point
to remote side's IP address across the Serial0/0 interface (preferred
solution) or create a layer 3 to layer 2 mapping for the destination of the
static route on the DLCI to the remote side. In an Ethernet environment
this isn't an issue due to the fact the remote routers are able to proxy ARP
for the destination.
The general rule is that when using static routes in a WAN environment you
shouldn't point the static route to an interface if it is a multipoint
interface.
--Brian Dennis, CCIE4 #2210 (R&S/ISP-Dial/Security/SP) bdennis@internetworkexpert.com Internetwork Expert, Inc. http://www.InternetworkExpert.com Toll Free: 877-224-8987 Direct: 775-745-6404 (Outside the US and Canada)
On 5/10/07 9:15 AM, "Sydney Hawke" <sydneyhawke@yahoo.com> wrote:
> Hi, > > I seem to miss somethng regarding EIGRP, GRE Tunnels, static route > > I have been testing EIGRP over a plain GRE tunnel and used static routes for > the destination networks of the tunnel. > > I tried to have a static route like this (over a frame-relay cloud): > > ip route 150.1.2.0 255.255.255.0 191.1.125.2 > > No problem and the tunnel interface do not have any output drops and here are > the details for the eigrp neighbor: > > ROUTER5#sh ip eigrp neig detail > IP-EIGRP neighbors for process 100 > H Address Interface Hold Uptime SRTT RTO Q Seq > (sec) (ms) Cnt Num > 0 25.25.25.2 Tu25 13 00:02:12 126 5000 0 118 > Version 12.4/1.2, Retrans: 9, Retries: 0, Prefixes: 2 > ROUTER5# > +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > This is the problem scenario and I do not understand what the problem is when > I use a static route with the interface as the next-hop??? > > Then I tried to use a static route like this: > > ip route 150.1.2.0 255.255.255.0 ser 0/0 > > ROUTER5#sh ip eigrp neig detail > IP-EIGRP neighbors for process 100 > H Address Interface Hold Uptime SRTT RTO Q Seq > (sec) (ms) Cnt Num > 0 25.25.25.2 Tu25 11 00:01:18 1 5000 1 0 > Version 12.4/1.2, Retrans: 16, Retries: 16, Waiting for Init, Waiting for > Init Ack > UPDATE seq 175 ser 0-0 Sent 78332 Init Sequenced > ROUTER5# > > *Mar 3 01:32:40.626: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 25.25.25.2 > (Tunnel25) is down: retry limit exceeded > > ROUTER5#sh ip eigrp neig detail > IP-EIGRP neighbors for process 100 > H Address Interface Hold Uptime SRTT RTO Q Seq > (sec) (ms) Cnt Num > 0 25.25.25.2 Tu25 14 00:00:00 1 2000 1 0 > Version 12.4/1.2, Retrans: 0, Retries: 0, Waiting for Init, Waiting for > Init Ack > UPDATE seq 177 ser 0-0 Sent 384 Init Sequenced > ROUTER5# > > *Mar 3 01:32:44.994: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 25.25.25.2 > (Tunnel25) is up: new adjacency > > ROUTER5# > And here are the output drops for the tunnel interface after I applied the > static route with an interface as the next-hop: > ROUTER5#sh int tun 25 > Tunnel25 is up, line protocol is up > Hardware is Tunnel > Internet address is 25.25.25.5/24 > MTU 1514 bytes, BW 9 Kbit, DLY 500000 usec, > reliability 255/255, txload 1/255, rxload 1/255 > Encapsulation TUNNEL, loopback not set > Keepalive not set > Tunnel source 150.1.5.5 (Loopback0), destination 150.1.2.2 > Tunnel protocol/transport GRE/IP > Key disabled, sequencing disabled > Checksumming of packets disabled > Tunnel TTL 255 > Fast tunneling enabled > Tunnel transmit bandwidth 8000 (kbps) > Tunnel receive bandwidth 8000 (kbps) > Last input 00:00:00, output 00:00:03, output hang never > Last clearing of "show interface" counters 00:32:06 > Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 122 > > > Best Regards, > > Sydney > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around > http://mail.yahoo.com > > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html
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