Kitz Forum

Broadband Related => Broadband Technology => Topic started by: Berrick on August 20, 2013, 12:25:13 PM

Title: Next hop IP address
Post by: Berrick on August 20, 2013, 12:25:13 PM

I hope this is the right place for this question?

Am I correct in assuming the next IP address I can ping after my default gateway is the Dslam?

Many thanks

Title: Re: Next hop IP address
Post by: kitz on August 20, 2013, 12:33:42 PM

It depends on which ISP youre with.   
LLU providers have their own routing system. 
BTw based ISPs usually see the next hop as being their ISP gateway as everything between the EU and gateway (ie BTs backhaul and core network) is L2TP tunnelled.

BT retail usually shows up some of the BTw core, with the next hop after your router being the RAS (http://www.kitz.co.uk/adsl/equip2.htm#RAS).

Title: Re: Next hop IP address
Post by: Berrick on August 20, 2013, 01:07:53 PM

TY Kitz, I'm with BT been trying to sort my other problem myself. With a different router I'm less prone to BB dropouts when I use the phone but regardless of which router I use I'm seeing some vary long ping times when pinging the next hop :(

Title: Re: Next hop IP address
Post by: roseway on August 20, 2013, 01:38:53 PM

That doesn't mean anything so far as your connection is concerned. It's quite common for internet routing sites to give a low priority to the ping response and highest priority to throughput. If you do a tracert to a site and see one of the hops having a high response time value but later hops having lower values, then the one with the high value is simply prioritising traffic in that way.

Title: Re: Next hop IP address
Post by: Berrick on August 20, 2013, 03:40:06 PM

Quote

It's quite common for internet routing sites to give a low priority to the ping response

I agree, ICMP ping always gets dropped in preference to data when the device being pinged is working hard or the device has an ICMP rate limit set. What I was trying to understand is whether the groups of long reply times was a result of the device I'm pinging being hammered, the frames where being routed differently or some other issue was causing them.

Generally I get good reply times from the next hop but suddenly they start going all over the place for short periods. To my knowledge I have never seen the affects of pinging a device which is actively discarding packets due to rate limiting. When this happens do you get a "request timed out" or does the device just not send a reply?