WCCP router identifier question

Unanswered Question
Jan 28th, 2008

Hi, all,

I have a subnet consist of a 2610XM router, a catalyst 2950(24 port). Since my router has only one FE port, it's configured as below:

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interface FastEthernet0/0

description CONNECTION TO CISCO_SW_PORT_24

no ip address

no ip proxy-arp

speed 100

full-duplex

no cdp enable

no mop enabled

!

interface FastEthernet0/0.2

description VLAN2_connect_to_outside

encapsulation dot1Q 2

ip address assigned_ip_addr 255.255.255.0

ip nat outside

ip virtual-reassembly

!

interface FastEthernet0/0.3

description VLAN3_192.168.1.0_inside_net

encapsulation dot1Q 3

ip address 192.168.1.1 255.255.255.0

ip nat inside

ip virtual-reassembly

!

interface FastEthernet0/0.4

description VLAN4 _192.168.3.0_inside_net

encapsulation dot1Q 4

ip address 192.168.3.1 255.255.255.0

ip nat inside

ip virtual-reassembly

!

interface FastEthernet0/0.5

description VLAN5_192.168.4.0_inside_net

encapsulation dot1Q 5

ip address 192.168.4.1 255.255.255.0

ip nat inside

ip virtual-reassembly

ip route 0.0.0.0 0.0.0.0 assigned_ip_addr_gateway

!

ip nat pool blackout assigned_ip_addr assigned_ip_addr netmask 255.255.255.0

ip nat inside source list 101 pool blackout overload

ip nat inside source static 192.168.1.100 assigned_ip_addr

access-list 101 permit ......

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The internal ip address 192.168.1.100 is assigned to a Fedora machine acting as a webserver, accessing vlan3. And the router FE port is connecting to one of the SW port as

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interface FastEthernet0/24

description TRUNK_CONNECTION_2610ROUTER_FE0/0

switchport mode trunk

no ip address

duplex full

speed 100

!

ip default-gateway 192.168.1.1

ip http server

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

The whole system works fine for above configuration. Now I want to add WCCP to the router as:

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

ip wccp web-cache

!

interface FastEthernet0/0.3

description VLAN3_192.168.1.0_inside_net

encapsulation dot1Q 3

ip address 192.168.1.1 255.255.255.0

ip wccp web-cache redirect in

ip nat inside

ip virtual-reassembly

!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Then, when I try a "show ip wccp" command on the router, the output looks like:

========================================

router#show ip wccp

Global WCCP information:

Router information:

Router Identifier: 192.168.4.1

Protocol Version: 2.0

Service Identifier: web-cache

Number of Service Group Clients: 1

Number of Service Group Routers: 1

Total Packets s/w Redirected: 4236

Process: 34

Fast: 0

CEF: 4202

Service mode: Open

......

========================================

It seems that the WCCP command is successfully sending packet to the server, becauce on the sever, when I try "tcpdump -n -i eth0 ip proto gre" the output looks like:

===============================================================

..........................

11:59:55.285674 IP 192.168.4.1 > 192.168.1.100: GREv0, length 68: gre-proto-0x883e

11:59:56.013556 IP 192.168.4.1 > 192.168.1.100: GREv0, length 68: gre-proto-0x883e

.........................

===============================================================

Here is my question: WHY THE ROUTER IDENTIFIER IS 192.168.4.1 WHILE NOT 192.168.1.1

The ip address 192.168.4.1 is in VLAN5 and I believe I did nothing to this VLAN both for the router configuration and the switch configuration. I just don't understand why wccp chooses FE0/0.5 as the router identifier.

Thanks in advance for any explanation.

Joe

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Overall Rating: 5 (1 ratings)
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owillins Fri, 02/01/2008 - 12:39

It (192.168.4.1) is the highest IP on the router and isn't used in terms of wccp conectivity. It's simply an identifier and has no impact on router.

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