Dual NBN connections, consistent link failures.

[ben-sharpibm]

Hi All,

We have deployed a Cisco 899G router to a site that has two NBN (Ethernet) connections to the provider on Gig8 and Gig9.

The connections are stable until one goes offline after 1800 seconds when the interface tries to renew its DHCP lease with the provider.

One of the interfaces then can't renew the connection and remains offline until it randomly renews again later.

Both connections are with the same ISP and I can see they use the same DHCP server but receive different IP addresses (as expected).

The DHCP server would have seen the same host name as both services terminate on the same router so I did this:

int g8

ip add dhcp client-id gig8 hostname NAME1

!

int g9

ip add dhcp client-id gig9 hostname NAME2

We still appear to be having issues with one connection unable to renew its IP address after the timer expires. It's completely random as to which interfaces timer will expire first - the one that expires first can keep renewing its IP without any issues, the other one experiences an outage for up to an hour while it tries to renew over and over again.

Thanks,

Ben

[Philip D'Ath]

I would run the gold start release of 15.4.3M7.

https://software.cisco.com/download/release.html?mdfid=286259493&softwareid=280805680&release=15.4.3M7&relind=AVAILABLE&rellifecycle=MD&reltype=latest

What are you running at the moment?

[ben-sharpibm]

Hi Philip,

Thanks for the reply. I have tried two different firmwares:

15.5.3.M4a

15.6.3.M2 (current)

Both experienced the same issue.

Regards,

Ben

[johnd2310]

Hi,

Is it not possible to get static ip addresses for your links?

Thanks

John

[ben-sharpibm]

Hi John,

As I understand the ISP (Telstra) only offers DHCP though their RADIUS servers which allows them to control the authentication. I will ask the question today though to confirm as this would be a viable solution.

I'm still unsure why the DHCP is causing issues - it shouldn't be.

Regards,

Ben