Thanks Rene,
I have another question, in the above section where u have mention about ARP request construct, I think the behavior of switches are different
The multilayer switch will check the routing table, notices that 192.168.20 /24 is directly connected and the following will happen:
The destination MAC address changes from FFF (Multilayer switch Fa0/1 ) to BBB (ComputerB).
The source MAC address changes from AAA (ComputerA) to GGG (Multilayer switch Fa0/2).===This seems to be Incorrect
I LAB this up with 3 switches (all real hardware 3550/3560) [ c3560-ipservicesk9-mz.122-55.SE10/ c3550-ipservicesk9-mz.122-44.SE6]
Simple topology- SW is just acting as regular sw with fa 0/23 & 19 as access port, SW2 and SW3 are acting like a end host (sort of PC with IP address on them)
SW2 -----------{fa 0/23 on both end}----------------SW1-----------{fa 0/19 on both end}-----------------SW3
When ARP request is created by SW2, its destination is always SW1 fa 0/19 and NOT fa 0/23 on SW1!, I also took packet capture and its shows the same thing,
Here is the relevant data, I will appreciate if you can review the config and attached screen shot and advise, Thanks Gary
------------------------------------------------------------------------------
SW1#sh int status | inc 0/19|0/23
Fa0/19 connected 1 a-full a-100 10/100BaseTX
Fa0/23 connected 1 a-full a-100 10/100BaseTX
SW1#sh cdp nei
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone,
D - Remote, C - CVTA, M - Two-port Mac Relay
Device ID Local Intrfce Holdtme Capability Platform Port ID
SW2 Fas 0/23 146 R S I WS-C3560- Fas 0/23
SW3 Fas 0/19 128 R S I WS-C3550- Fas 0/19
!!! Before PING, SW1 MAC table don’t have any dynamic entry!!!
SW1#sh mac address-table
Mac Address Table
-------------------------------------------
Vlan Mac Address Type Ports
---- ----------- -------- -----
All 0100.0ccc.cccc STATIC CPU
All 0100.0ccc.cccd STATIC CPU
All 0180.c200.0000 STATIC CPU
All 0180.c200.0001 STATIC CPU
All 0180.c200.0002 STATIC CPU
All 0180.c200.0003 STATIC CPU
All 0180.c200.0004 STATIC CPU
All 0180.c200.0005 STATIC CPU
All 0180.c200.0006 STATIC CPU
All 0180.c200.0007 STATIC CPU
All 0180.c200.0008 STATIC CPU
All 0180.c200.0009 STATIC CPU
All 0180.c200.000a STATIC CPU
All 0180.c200.000b STATIC CPU
All 0180.c200.000c STATIC CPU
All 0180.c200.000d STATIC CPU
All 0180.c200.000e STATIC CPU
All 0180.c200.000f STATIC CPU
All 0180.c200.0010 STATIC CPU
All ffff.ffff.ffff STATIC CPU
1 0015.2b95.4c00 DYNAMIC Fa0/19
1 0023.05c6.b6c1 DYNAMIC Fa0/23
Total Mac Addresses for this criterion: 22
SW2#sh run int fa 0/23
Building configuration...
Current configuration : 86 bytes
!
interface FastEthernet0/23
no switchport
ip address 10.10.12.2 255.255.255.0
end
!!! Before PING, SW2 MAC table don’t have any dynamic entry!!!
SW2#sh mac address-table
Mac Address Table
-------------------------------------------
Vlan Mac Address Type Ports
---- ----------- -------- -----
All 0100.0ccc.cccc STATIC CPU
All 0100.0ccc.cccd STATIC CPU
All 0180.c200.0000 STATIC CPU
All 0180.c200.0001 STATIC CPU
All 0180.c200.0002 STATIC CPU
All 0180.c200.0003 STATIC CPU
All 0180.c200.0004 STATIC CPU
All 0180.c200.0005 STATIC CPU
All 0180.c200.0006 STATIC CPU
All 0180.c200.0007 STATIC CPU
All 0180.c200.0008 STATIC CPU
All 0180.c200.0009 STATIC CPU
All 0180.c200.000a STATIC CPU
All 0180.c200.000b STATIC CPU
All 0180.c200.000c STATIC CPU
All 0180.c200.000d STATIC CPU
All 0180.c200.000e STATIC CPU
All 0180.c200.000f STATIC CPU
All 0180.c200.0010 STATIC CPU
All ffff.ffff.ffff STATIC CPU
Total Mac Addresses for this criterion: 20
SW3#sh run int fa 0/19
Building configuration...
Current configuration : 86 bytes
!
interface FastEthernet0/19
no switchport
ip address 10.10.12.3 255.255.255.0
end
!!! Before PING, SW3 MAC table don’t have any dynamic entry!!!
SW3#sh mac address-table
Mac Address Table
-------------------------------------------
Vlan Mac Address Type Ports
---- ----------- -------- -----
All 0015.2b95.4c00 STATIC CPU
All 0015.2b95.4c01 STATIC CPU
All 0015.2b95.4c02 STATIC CPU
All 0015.2b95.4c03 STATIC CPU
All 0015.2b95.4c04 STATIC CPU
All 0015.2b95.4c05 STATIC CPU
All 0015.2b95.4c06 STATIC CPU
All 0015.2b95.4c07 STATIC CPU
All 0015.2b95.4c08 STATIC CPU
All 0015.2b95.4c09 STATIC CPU
All 0015.2b95.4c0a STATIC CPU
All 0015.2b95.4c0b STATIC CPU
All 0015.2b95.4c0c STATIC CPU
All 0015.2b95.4c0d STATIC CPU
All 0015.2b95.4c0e STATIC CPU
All 0015.2b95.4c0f STATIC CPU
All 0015.2b95.4c10 STATIC CPU
All 0015.2b95.4c11 STATIC CPU
All 0015.2b95.4c12 STATIC CPU
All 0015.2b95.4c13 STATIC CPU
All 0015.2b95.4c14 STATIC CPU
All 0015.2b95.4c15 STATIC CPU
All 0015.2b95.4c16 STATIC CPU
All 0015.2b95.4c17 STATIC CPU
All 0015.2b95.4c18 STATIC CPU
All 0015.2b95.4c19 STATIC CPU
All 0015.2b95.4c1a STATIC CPU
All 0100.0c00.0000 STATIC CPU
All 0100.0ccc.cccc STATIC CPU
All 0100.0ccc.cccd STATIC CPU
All 0100.0ccd.cdce STATIC CPU
All 0180.c200.0000 STATIC CPU
All 0180.c200.0001 STATIC CPU
All 0180.c200.0002 STATIC CPU
All 0180.c200.0003 STATIC CPU
All 0180.c200.0004 STATIC CPU
All 0180.c200.0005 STATIC CPU
All 0180.c200.0006 STATIC CPU
All 0180.c200.0007 STATIC CPU
All 0180.c200.0008 STATIC CPU
All 0180.c200.0009 STATIC CPU
All 0180.c200.000a STATIC CPU
All 0180.c200.000b STATIC CPU
All 0180.c200.000c STATIC CPU
All 0180.c200.000d STATIC CPU
All 0180.c200.000e STATIC CPU
All 0180.c200.000f STATIC CPU
All 0180.c200.0010 STATIC CPU
Total Mac Addresses for this criterion: 48
SW2#sh int fa 0/23
FastEthernet0/23 is up, line protocol is up (connected)
Hardware is Fast Ethernet, address is 0023.05c6.b6c1 (bia 0023.05c6.b6c1)
Internet address is 10.10.12.2/24
SW1#sh int fa 0/19
FastEthernet0/19 is up, line protocol is up (connected)
Hardware is Fast Ethernet, address is 0023.05cb.2815 (bia 0023.05cb.2815)
SW1#sh int fa 0/23
FastEthernet0/23 is up, line protocol is up (connected)
Hardware is Fast Ethernet, address is 0023.05cb.2819 (bia 0023.05cb.2819)
SW3#sh int fa 0/19
FastEthernet0/19 is up, line protocol is up (connected)
Hardware is Fast Ethernet, address is 0015.2b95.4c00 (bia 0015.2b95.4c00)
Internet address is 10.10.12.3/24
!!! AFTER PING, SW1 MAC table now having dynamic entry and notice the MAC address is of SW2 and SW3!!!
SW1#sh mac address-table
Mac Address Table
-------------------------------------------
Vlan Mac Address Type Ports
---- ----------- -------- -----
All 0100.0ccc.cccc STATIC CPU
All 0100.0ccc.cccd STATIC CPU
All 0180.c200.0000 STATIC CPU
All 0180.c200.0001 STATIC CPU
All 0180.c200.0002 STATIC CPU
All 0180.c200.0003 STATIC CPU
All 0180.c200.0004 STATIC CPU
All 0180.c200.0005 STATIC CPU
All 0180.c200.0006 STATIC CPU
All 0180.c200.0007 STATIC CPU
All 0180.c200.0008 STATIC CPU
All 0180.c200.0009 STATIC CPU
All 0180.c200.000a STATIC CPU
All 0180.c200.000b STATIC CPU
All 0180.c200.000c STATIC CPU
All 0180.c200.000d STATIC CPU
All 0180.c200.000e STATIC CPU
All 0180.c200.000f STATIC CPU
All 0180.c200.0010 STATIC CPU
All ffff.ffff.ffff STATIC CPU
1 0015.2b95.4c00 DYNAMIC Fa0/19 -----!!!!!This is MAC of 0/19 on sw3
1 0023.05c6.b6c1 DYNAMIC Fa0/23-----!!!!!This is MAC of 0/23 on sw2
Total Mac Addresses for this criterion: 22