Bridging FR MP

From: Luca Hall (lhall@setnine.com)
Date: Wed Apr 23 2008 - 11:26:44 ART


I am trying to bridge over two multi point frame-relay interfaces:

        fr-mp fr-mp
   BVI1-R1 --- FRSW --- R4-BVI1
145.1.1.1 104 401 145.1.1.4

R1
+++++
bridge irb

interface Serial0/0.145 multipoint
 no ip route-cache
 frame-relay map bridge 104 broadcast
 frame-relay map ip 145.1.1.4 104 broadcast
 bridge-group 1
end

interface BVI1
 mac-address 00c0.1111.1111
 ip address 145.1.1.1 255.255.255.0

bridge 1 protocol ieee
bridge 1 route ip

R4
+++++
bridge irb

interface Serial0/0.145 multipoint
 no ip route-cache
 frame-relay map bridge 401 broadcast
 frame-relay map ip 145.1.1.1 401 broadcast
 bridge-group 1

interface BVI1
 mac-address 00c0.4444.4444
 ip address 145.1.1.4 255.255.255.0

bridge 1 protocol ieee
bridge 1 route ip

When both sides are multipoint you will never see the other sides
MAC in a 'sh arp', so I thought that this may have something to do
with inverse-arp since a difference is that on multipoint inverse-arp
requests are disabled. But even with inverse-arp disabled on both sides
and all revelant tables cleared this will still work p2p <-> mp.
Doing a static arp mapping on either side mp <-> mp will also work.

r4#sh frame map
Serial0/0.145 (up): bridge dlci 401(0x191,0x6410), static,
              broadcast,
              CISCO, status defined, active
Serial0/0.145 (up): ip 145.1.1.1 dlci 401(0x191,0x6410), static,
              broadcast,
              CISCO, status defined, active
MFR0.1 (down): point-to-point dlci, dlci 45(0x2D,0x8D0), broadcast
          status defined, inactive

r4#sh frame pvc | i \ ACTIVE
DLCI = 401, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE =
Serial0/0.145

r4#sh ip int brief | i up
Serial0/0 unassigned YES NVRAM up
 up
Serial0/0.145 unassigned YES unset up
 up
BVI1 145.1.1.4 YES NVRAM up
 up

r4#sh span br

Bridge group 1
  Spanning tree enabled protocol ieee
  Root ID Priority 32768
             Address 0000.0cc6.58b8
             Cost 7812
             Port 21 (Serial0/0.145)
             Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

  Bridge ID Priority 32768
             Address 0000.0ceb.7418
             Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
             Aging Time 300

Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID
Port ID
-------------------- ------- ---- ----- --- ----- --------------------
-------
Serial0/0.145 128.21 128 7812 FWD 0 32768 0000.0cc6.58b8 128.17

r4#sh int irb
Serial0/0.145

 Routed protocols on Serial0/0.145:
  ip

 Bridged protocols on Serial0/0.145:
  appletalk clns decnet ip

BVI1

 Routed protocols on BVI1:
  ip

r4#ping 145.1.1.1 rep 1

Type escape sequence to abort.
Sending 2, 100-byte ICMP Echos to 145.1.1.1, timeout is 2 seconds:

IP: tableid=0, s=145.1.1.4 (local), d=145.1.1.1 (Serial0/0.145), routed
via FIB
IP: s=145.1.1.4 (local), d=145.1.1.1 (Serial0/0.145), len 100, sending
     ICMP type=8, code=0.

Changing either side to a point-to-point this works fine,

eg.

interface Serial0/0.14 point-to-point
 no ip route-cache
 frame-relay interface-dlci 104
 bridge-group 1
end

r1#ping 145.1.1.4

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 145.1.1.4, timeout is 2 seconds:
..!!!
Success rate is 60 percent (3/5), round-trip min/avg/max = 36/36/36 ms
r1#sh arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 145.1.1.1 - 00c0.1111.1111 ARPA BVI1
Internet 145.1.1.4 0 00c0.4444.4444 ARPA BVI1

So my question is why dont arp requests bridged over frame relay work
when both sides of the link are point-to-multipoint? I know I'm just
missing something easy about the arps, maybe bridged frames and
eth arps vs fr inverse arps?

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This archive was generated by hypermail 2.1.4 : Thu May 01 2008 - 08:25:51 ART