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New Member

7206VXR router and VLAN Illegal access to a low address error

Hi all,

We've had our 7206 up and running for several weeks now, and have begun to implement a more complex design using VLANs.

Current config for the interface in question:

interface FastEthernet0/0

description ** Link to coresw **

ip address 111.111.111.111 255.255.255.0

no ip redirects

no ip unreachables

no ip proxy-arp

ip accounting access-violations

ip multicast boundary 30

ip route-cache flow

no ip mroute-cache

duplex auto

speed auto

no cdp enable

!

I'm trying to add:

interface FastEthernet0/0.1

description VLAN 1

encapsulation dot1Q 1

no ip redirects

no cdp enable

!

as a virtual VLAN interface, and am getting the router rebooting, throwing the following to console:

%ALIGN-1-FATAL: Illegal access to a low address

addr=0x40, pc=0x6049676C, ra=0x6049578C, sp=0x624E6F48

%ALIGN-1-FATAL: Illegal access to a low address

addr=0x40, pc=0x6049676C, ra=0x6049578C, sp=0x624E6F48

-Traceback= 6049676C 6049940C 600F1BF0 6011AF50

signal= 0xA, code= 0x40C, context= 0x6220BA70

I've done searches and believe the error is as follows, but if anyone can agree or disagree with that it would be most usefull, as unfortunately this network is now live, so I have to be somewhat delicate on config changes!

"CSCin22287

Symptoms: A router may permanently pause with the following error message:

%ALIGN-1-FATAL: Illegal access to a low address-box crash

Conditions: This symptom is observed on a Cisco router when there is active traffic on the subinterface and the VLAN encapsulation is changed.

Workaround: Shut down the subinterface before changing the encapsulation, and then reload the subinterface after the encapsulation change is complete."

Thanks!!

Andy.

1 REPLY
New Member

Re: 7206VXR router and VLAN Illegal access to a low address erro

Your main interface should have no config apart from possibly a description and a no shut. This has to do with the fact that you want to "divide" your interface into subs using vlan encapsulation (ISL / Dot1q) which then turns this interface into a controller for the channel if you will. Change your config to something like this :

int f0/0

no shut

description physical interface for subs

int f0/0.1

description ** Link to coresw **

encaps dot1q 1

ip address 111.111.111.111 255.255.255.0

int f0/0.2

description link to vlan 1

encaps dot1q 2

ip x.x.x.x y.y.y.y

This should sort out the problem:)

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