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New Member

checking link quality

Hi all,

This question is haunting me for quite some time and i really need some experience of you guys to help me.

We have branches all over the country and we take different links like fiber (ethernet) radio links etc. Now sometimes when we ping from branch WAN ip to its gateway or to the aggregation router (ASR 1000) in this case, we see some drops, but see no problem in actual http or lotus communication. What i want to know, that now a days, should we rely on ping results to determine link quality ? or should i use tools like iperf to basically see if the link is actually treating tcp and udp packets properly, I have heard this countless times that normally network devices like cisco routers, even without any qos, will give low priority to ping packets.

As you can see i am lot confused. Need some expert input pls

New Member

Re: checking link quality

An interesting question. In terms of ICMP you could alway ping between hosts behind your routers for manual testing. However for automated testing then ip sla would be the way to go. Also some traffic types are more tolerant of loss than others. For example TCP traffic e.g. HTTP can recover from lost segments whereas UDP cannot (unless this is done at an upper layer of course like in TFTP or SIP). UDP is used extensively for real time traffic like voice vans video, so those applications would become unusable if there is high packet loss, delay, or jitter (variance in delay).

Ip sla allow you setup monitors for different types of traffic as required, which can then tracked and thus generate management information.

Tools like this form the basis for Pfr (formerly OER) but this is probably out of scope for this post.

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