From: Reza Toghraee (reza@toghraee.com)
Date: Sun Sep 23 2007 - 11:30:43 ART
Hi
Let's do a trace.
1) R5 with local IP of 150.50.7.5/25 tries to send an ICMP packet to
150.50.7.6/25
2) R5 founds that the destination address is a member of the 150.50.7.0/25
network which F0/0 is an attached interface to it.
3) R5 sends an ARP request with source of F0/0 MAC address and destination
of broadcast (FF:FF:FF:FF) out the F0/0 interface.
4) SW1 receives the ARP frame from its F1/5 interface which is inside the
VLAN 567
5) SW1 checks the destination address which is broadcast frame, so it should
be forwarded over all ports in VLAN 567 and trunk ports.
6) SW1 encapsulates the arp in a .1Q or ISL frame and sends out to F1/6
7) Sw2 receives a frame for VLAN 567, cut off the vlan headers, it knows
it's a broadcast frame, and forwards to all ports on 567 vlan
8) SW2 forwards the frame to F1/6 interface
9) R6 receives an ARP with its IP as destination. Creates the REPLY, through
the R1
10) the same way from R6 to R1 for ARP-REPLY
So maybe the problem from the Dynamips ?
Reza
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
George Goglidze
Sent: Sunday, September 23, 2007 5:35 PM
To: ccielab@groupstudy.com
Subject: switching problem
Hello all,
I've started to do ip3xpert labs, and it's one of the first ones.
but I got stuck in one problem, which I don't know if is dynamips bug, or my
config,
most probably it's my config :)
the routers are 3640 model, switches are the 3640 routers too but with
switch module NM-16ESW.
diagram is following -> R5 f0/0 <----> f1/5 SW1 f0/1 <----> f0/1 SW2
f1/6<----> f0/0 R6
link between SW1 and SW2 is trunk.
following config:
SW1#sh run int f0/1
Building configuration...
Current configuration : 56 bytes
!
interface FastEthernet0/1
switchport mode trunk
SW2#sh run int f0/1
Building configuration...
Current configuration : 56 bytes
!
interface FastEthernet0/1
switchport mode trunk
------------
I have created VLAN 567 on SW1, and i can see that vlan replicates ok to
SW2.
on SW1 port f1/5 is in VLAN 567, and in SW2 port f1/6 is in VLAN 567 too.
here's config:
SW1#sh run int f1/5
Building configuration...
Current configuration : 61 bytes
!
interface FastEthernet1/5
switchport access vlan 567
end
SW2#sh run int f1/6
Building configuration...
Current configuration : 61 bytes
!
interface FastEthernet1/6
switchport access vlan 567
end
the link's are all UP UP.
on R1 int f0/0 has ip: 150.50.7.5 255.255.255.128
on R2 int f0/0 has ip: 150.50.7.6 255.255.255.128
but I can't ping one from another.
I tried following tests.
1) on SW1 I created interface VLAN 567, and put ip: 150.50.7.13
255.255.255.128
SW1#sh run int vlan 567
Building configuration...
Current configuration : 84 bytes
!
interface Vlan567
ip address 150.50.7.13 255.255.255.128
no ip route-cache
end
and from R1 I still can't ping this ip, output with debug on:
R5#debug ip packet
IP packet debugging is on
R5#ping 150.50.7.13 rep 1
Type escape sequence to abort.
Sending 1, 100-byte ICMP Echos to 150.50.7.13, timeout is 2 seconds:
*Mar 1 03:00:43.279: IP: tableid=0, s=150.50.7.5 (local),
d=150.50.7.13(FastEthernet0/0), routed via RIB
*Mar 1 03:00:43.279: IP: s=150.50.7.5 (local),
d=150.50.7.13(FastEthernet0/0), len 100, sending
*Mar 1 03:00:43.279: IP: s=150.50.7.5 (local),
d=150.50.7.13(FastEthernet0/0), len 100, encapsulation failed.
Success rate is 0 percent (0/1)
R5#
I have encapsulation failed, it can't resolve IP to MAC address.
2) if on SW1 I remove switchport on f1/5 and make it ip interface everything
works fine when I put ip 150.50.7.13 255.255.255.128.
I can ping this ip from R5.
If anyone has any idea, please let me know, I'm really frustrated...
Thank you very much.
**
This archive was generated by hypermail 2.1.4 : Sat Oct 06 2007 - 12:01:15 ART