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cause of ping responce

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15 years 11 months ago #27598 by rafi
cause of ping responce was created by rafi
what is the cause of high responce time.
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15 years 11 months ago #27614 by Smurf
Replied by Smurf on topic Re: cause of ping responce
This can depend on the different hops that is taken to reach the destination host. If you ping something on the internet, then it will go through several gateways with varying sizes of links. As it passes through these links, it takes longer for the response to get back. Since there are often different routes to the same host, you can get varying response times as it goes over links of different speeds.

If you do the pathping, it will do a ping and tracert together which can sometimes be interesting.

(i think PathPing was introduced in Windows 2000 and above)

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Wayne

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15 years 11 months ago #27637 by ZiPPy
Replied by ZiPPy on topic Re: cause of ping responce
I agree with Smurf that the ping response time will depend on how many hops it takes to reach the destination. Now we can also say that the packet will always take the best known route (fastest route) possible each time, respectively. Correct?

I have noticed high ping response times along with decent response times, but with dropped packets. Do you assume the route is the problem or the hardware within the LAN. Packet loss will vary from 40% to 50% when doing an infinite ping.

I have a feeling the problem is the switch. No matter what port I use on the switch, I get the 40% to 50% packet loss. The switch has 48 ports (10/100) but it also has 4 (10/100/1000) ports labeled G1 - G4. It also has 2 fiber channels. When I plug into any of the G1 - G4 ports the packet loss stops. Would you agree that the ports on the 10/100 are going bad? I can't find any other explanation of why packet loss stops when I plug into the giga ports.


Cheers,

ZiPPy

ZiPPy
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15 years 11 months ago #27639 by S0lo
Replied by S0lo on topic Re: cause of ping responce

Now we can also say that the packet will always take the best known route (fastest route) possible each time, respectively. Correct?


Yes, but not always. For example when using a primitive routing protocol like RIP. The path cost depends only on the hop count regardless of the link speeds. As Smurf mentioned, links can have varying speeds, so a route with say three 100Mps links can be faster than a route with only one 10Mps link. Still dumb RIP doesn't see this, it will always take the 10Mps one link route.

I have noticed high ping response times along with decent response times, but with dropped packets. Do you assume the route is the problem or the hardware within the LAN. Packet loss will vary from 40% to 50% when doing an infinite ping.

I have a feeling the problem is the switch. No matter what port I use on the switch, I get the 40% to 50% packet loss. The switch has 48 ports (10/100) but it also has 4 (10/100/1000) ports labeled G1 - G4. It also has 2 fiber channels. When I plug into any of the G1 - G4 ports the packet loss stops. Would you agree that the ports on the 10/100 are going bad? I can't find any other explanation of why packet loss stops when I plug into the giga ports.


40% to 50% is extremely high!!. Whats the "duplex" setting on your switch's ports? Duplex mismatch can some times cause such problems. PCs (windows) are set to "Auto" by default. Set both PC and switch to the same. Still, your case is a little odd with the Gig ports working OK!!! :o. Does it happen even when you ping a host/router directly connected to your switch? Or is it specific to a remote host/router?

Studying CCNP...

Ammar Muqaddas
Forum Moderator
www.firewall.cx
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15 years 11 months ago #27640 by ZiPPy
Replied by ZiPPy on topic Re: cause of ping responce
The switch ports are set to full duplex mode. Yes, it still happens when I ping the host/router. All devices are connected directly to the switch, no remote host/router.

Now the giga ports G1 and G2 are both shared with the fibre channels. This is labeled on the front of the switch. I don't quite understand how that works. But if they are shared with the fibre channel I would think a setting is different for those G ports that would possibly eliminate the dropped packet issue.

But I still don't think that would be accurate either, BECAUSE the switch has been working just fine up until now. I honestly must say this is one of those odd switching issues, OR simply a switching dying very slowly.


ZiPPy

ZiPPy
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15 years 11 months ago #27643 by S0lo
Replied by S0lo on topic Re: cause of ping responce
Zippy, just to clear the possibility, try setting 2 of the (10/100) ports to "duplex auto", connect two PCs and ping between them.

By default NICs on PCs are set to "auto" (auto-negotiation). Unless you have changed this in the "Device Manager", the other side (switch) should be on "auto" too.

Studying CCNP...

Ammar Muqaddas
Forum Moderator
www.firewall.cx
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