[Asterisk-Users] Re: Re: How is Teliax ?

Steven asterisk at tescogroup.com
Mon Apr 3 07:15:16 MST 2006


traceroute can't necessarily tell you how good a connection is, but it can tell you how bad it is.
seeing as ICMP is usually first to be dropped, a good traceroute can be indicative of no congestion.
And a bad traceroute may be indicative of congestion.

-- 
-- 
Steven

http://www.glimasoutheast.org



"Rich Adamson" <radamson at routers.com> wrote in message news:442E8610.9090600 at routers.com...
>> I would not ride on a tracert too much. We use Teliax also and our ISP that
>> we have at the data center switched there backbones around the same time
>> Teliax where doing there upgrades.
>
> For those that have not analyzed how tracert actually works, you can't depend on its output to give you factual evidence as to 
> where delays occur in an end-to-end path. Each step through the tracert process does nothing more then issue an icmp echo request, 
> measuring the response time and displaying it. When a high value is reported (eg, at router #10 for example), there is no way to 
> know (factually) whether that high response was from that particular device (#10) or one of the routers prior to that address (eg, 
> #3, #5, or #9). All you really know is that at the time the icmp was sent, the response was delayed for some reason, and it could 
> have been any of the devices prior to the specific one that you thought was the issue.
>
>> We started seeing some call issues and when we did a tracert we started
>> getting some dropped tracert responses on our ISP new backbone(Time Warner)
>> when our ISP investigated it Time Warner responded that tracerts get a VERY
>> low priority on their routers and that is why we where seeing these drops.
>
> The "low priority" comment is one that was started by Cisco folks many years ago when router processors were taxed much heavier 
> then current day products. Back then, Cisco IOS firmware prioritized various events and icmp's were (and still are) low priority 
> events. However, since then the processor speeds have significantly increased and off-loading of many routing events to card-level 
> processors have occurred. The processing of icmp traffic is seldom (if ever) impacted in any measurable way in products 
> manufactured in the last five to ten years.
>
>> Once Teliax did whatever their last change was fixed all of our issue and we
>> have not see any call issue in the last 2-3 weeks. Still see drops on the
>> traces. I would look more at the latency and for dropped packets if you do a
>> continues ping with setting the size to something other then default and see
>> if you get any dropped packets or high latency.
>
> Right on!
>
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