ASR 9006 AS A BNG ，recently some users will not connection and Currently the main problem is “Duplicate IPv4 Address”

[mqw071201]

We have an ASR9006 in one of the projects which is working as BNG and have around 30k subscriber.

Recently there are some problem which session of some users will not complete and so they don`t have connection.

Currently the main problem is “Duplicate IPv4 Address” and as in our scenario AAA has the responsibility of IP pool to assign the ip address to the user and as AAA will see some online users as offline so it will release the ip and will assign to another user while existing user has the same IP and duplicate will happen.

It seems there is a bug which prevent BRAS to send right accounting information to AAA.

[mqw071201]

this log buffer : RP/0/RSP1/CPU0:Apr 30 04:01:22.798 : PPP-MA[377]: %L2-PPP_MA-4-ERR_RIB : Unexpected error encountered whilst Sending RIB batch buffer, error 1 RP/0/RSP1/CPU0:Apr 30 04:01:22.798 : PPP-MA[377]: %L2-PPP_MA-3-ERR_DUPLICATE_IPV4_ADDRESS : Bundle-Ether10.22050.pppoe14855: Subscriber IPv4 address 2.183.49.129 matches another route RP/0/RSP1/CPU0:Apr 30 04:01:22.799 : ipv4_rib[1153]: %ROUTING-RIB-3-ERR_DELETE : Path delete failure for Table 0xe0000000, prefix 2.183.49.129/32, protocol subscriber, intf 0x2131be0, tunnelid 0, nexthop_table 0xe0000000, nexthop 0.0.0.0 RP/0/RSP1/CPU0:Apr 30 04:03:19.175 : ipv4_rib[1153]: %ROUTING-RIB-3-ECMP_ERR_ADD : Path add exceed max number of paths supported by protocol. Table 0xe0000000, prefix 2.183.49.129/32, protocol subscriber, intf 0x23888a0, tunnelid 0, nexthop_table 0xe0000000, nexthop 0.0.0.0 RP/0/RSP1/CPU0:Apr 30 04:03:19.175 : PPP-MA[377]: %L2-PPP_MA-4-ERR_RIB : Unexpected error encountered whilst Sending RIB batch buffer, error 1 RP/0/RSP1/CPU0:Apr 30 04:03:19.176 : PPP-MA[377]: %L2-PPP_MA-3-ERR_DUPLICATE_IPV4_ADDRESS : Bundle-Ether1.2050.pppoe15713: Subscriber IPv4 address 2.183.49.129 matches another route

[Aleksandar Vidakovic]

are you running the XR release 5.3.3 with the latest Service Pack or with all the BNG related SMUs installed?

If periodic accounting is configured but the BNG doesn't send the messages, we should look into that more closely. It would be the best if you would open a TAC SR.

regards,

Aleksandar

[xthuijs · Accepted solution]

also check show radius to see if there were accounting messages dropped.

possibly add a retry if the accounting server is busy

maybe it is a nice idea in the radius server to verify with a coa query to see if there is an account online with that address already. but that is optional of course.

regards

xander

[mqw071201]

Hi Xander :

                Thank you for your answer！The attachment for the radius server log，May be helpful to us.pl check,Looking forward to your reply。

thanks a lot 

[xthuijs]

looking at the log I dont see any reason for the dupe addr handout, but I do see a lot of invalid/incomplete records.

the dupe addr comes from teh fact of lost accounting stop messages so best to verify the show radius stat for that.

meanwhile if you are not on 533 with latest sp, that might be a good starting point to see if the rogue records disappear and the dupe attributes they sometimes contain it looks.

if that continues to exist I think we'll need a tac case to have a ddts filed and have this investigated from sw standpoint.

regards!

xander