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mstokes
Beginner
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Message 1 of 8

Infinity speed test variation between PCs

I have recently upgraded from an old Demon ADSL to a 40/10 FTTC service from BT, from Walton-on-Thames cabinet 8.  I am using a third party router (Draytek 2860).  Presently I regularly use three different PCs on the network.

 

Two of those PCs are delivering the service I am expecting (40/10 Mb/s, 9mS latency).  One is not (9/7 Mb/s).

 

Running PingPlotter (a combined ping/trace route utility) on a 'good' machine has no ping returns until around hop 6 which is a 213 dot (telhouse.ukcore) address.

 

The 'bad' machine gets ping returns from hop 3 which is a 31.55.186.xxx IP, probably on the same subnet as the auto-configured DNS server.  This IP is showing a very high packet loss, around 50% which I suspect is the cause of my speed loss on that particular machine.

 

My suspicion is that the two PCs are taking different routes (even though they are both tracing to the same end point, bbc.co.uk).  One is returning pings at hop 3 , the other is not.  I have tried a ping to the adjacent numbers to the 'faulty' one and one times out with no return, which is what I would expect.

 

This raises the question, is 31.55.186.197 mis-configured? Is it returning pings when it should be configured not to?

 

I have just re-run the PingPlotter to confirm those details and I notice now that the 'faulty' PC is now routing via 31.55.186.193, which is also returning pings (so I know the address) and which is also showing high packet loss, so the speed is still down.

 

Is this something that anyone else has noticed?  I am still open to suggestions that there is something different about this one PC but I am running out of configuration options to check!

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7 REPLIES 7
Distinguished Sage
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Message 2 of 8

Re: Infinity speed test variation between PCs

hop 3 is set like some others not to respond to pings and it is perfectly normal
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mstokes
Beginner
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Message 3 of 8

Re: Infinity speed test variation between PCs

Thanks John.  I would expect that to be the case but in fact one machine test prompts a ping return, the other does not.

 

Having read of a similar issue recently reported, I have done a Windows trace route from the slow PC:

 

Tracing route to www.bbc.net.uk [212.58.246.90]
over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms 192.168.1.1
2 * * * Request timed out.
3 6 ms 7 ms 7 ms 31.55.186.193
4 7 ms 7 ms 6 ms 31.55.186.208
5 7 ms 7 ms 7 ms 195.99.127.42
6 7 ms 7 ms 7 ms peer2-
et-1-1-0.telehouse.ukcore.bt.net [213.121.193.163]
7 7 ms 6 ms 7 ms 194.74.65.42
8 * * * Request timed out.
9 8 ms 8 ms 8 ms ae0.er01.
cwwtf.bbc.co.uk [132.185.254.93]
10 8 ms 8 ms 8 ms 132.185.255.165
11 8 ms 7 ms 7 ms
bbc-vip011.cwwtf.bbc.co.uk [212.58.246.90]

Trace complete.

 

And now the trace route from the faster one:

 

Tracing route to www.bbc.net.uk [212.58.244.69]
over a maximum of 30 hops:

1 71 ms 1 ms 1 ms 192.168.1.1
2 * * * Request timed out.
3 * * 6 ms 31.55.186.193
4 7 ms 7 ms 6 ms 31.55.186.224
5 7 ms 7 ms 7 ms core4-hu0-16-0-1.
faraday.ukcore.bt.net [195.99.127.204]
6 8 ms 7 ms 7 ms peer2-
et-9-1-0.telehouse.ukcore.bt.net [213.121.193.167]
7 7 ms 7 ms 7 ms 194.74.65.42
8 * * * Request timed out.
9 * * * Request timed out.
10 7 ms 7 ms 7 ms ae0.er01.
telhc.bbc.co.uk [132.185.254.109]
11 8 ms 8 ms 8 ms 132.185.255.148
12 7 ms 7 ms 7 ms
bbc-vip114.telhc.bbc.co.uk [212.58.244.69]

Trace complete.

 

The routes are subtly different. 

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ChrisFWood
Aspiring Contributor
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Message 4 of 8

Re: Infinity speed test variation between PCs

Are they all using wired or wireless connections.

 

I can't think of a reason why the route would be different between two systems on the same network.

 

I am sure the routing tables of each device just know the default route and any specific routes i.e. 192.168.0.1/24 get routed to the local lan everything else goes to the default (BT gateway) that will know anything for each BT customer will go to the vsdl for that customer the rest to the next hop to the internet backbone.

 

If you are on wifi maybe you are connected to the wrong network i.e. a local open wifi channel or a spoofed ssid matching your ssid. hence the different route.

 

My route tables looks like this:

Key: C - connected, S - static, R - RIP, * - default, ~ - private
*            0.0.0.0/ 0.0.0.0          via 213.120.155.224   WAN1
*    213.120.155.224/ 255.255.255.255  via 213.120.155.224   WAN1
S      86.151.125.371/ 255.255.255.255  via 86.151.125.371     WAN1 🙂 edited and yes I know 371 will never work
C~       192.168.1.0/ 255.255.255.0    directly connected    LAN1
C~       192.168.2.0/ 255.255.255.0    directly connected    LAN2

 

And a far as the gateway i.e. 213.120.155.224 is concerned everything come from my draytec, the IPv6 it get a touch more complex as every device has at least one public IP as I have enough addresses to play with.

 

Destination                                  Interface Flags     Metric    Next Hop                                     
2001:470:1F09:9e10::/64                       LAN1      U         256       ::                                           
2001:470:1F09:9e10::/64                       LAN2      U         256       ::                                           
FE80::/64                                    LAN1      U         256       ::                                           
FE80::/64                                    LAN2      U         256       ::                                           
FE80::/64                                    LAN3      U         256       ::                                           
FE80::/64                                    LAN4      U         256       ::                                           
FE80::/64                                    LAN5      U         256       ::                                           
FE80::/64                                    LAN6      U         256       ::                                           
FE80::/64                                    DMZ       U         256       ::                                           
FE80::/64                                    WAN1      U         256       ::                                           
FF00::/8                                     LAN1      U         256       ::                                           
FF00::/8                                     LAN2      U         256       ::                                           
FF00::/8                                     LAN3      U         256       ::                                           
FF00::/8                                     LAN4      U         256       ::                                           
FF00::/8                                     LAN5      U         256       ::                                           
FF00::/8                                     LAN6      U         256       ::                                           
FF00::/8                                     DMZ       U         256       ::                                           
FF00::/8                                     WAN1      U         256       ::                                           
::/0                                         WAN1      UAF       1024      ::                                           

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ChrisFWood
Aspiring Contributor
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Message 5 of 8

Re: Infinity speed test variation between PCs

You have noticed the two systems are talking to two different addresses hence the route will be different haven't you.

 

Try ipconfig /flushdns on the problem one.

nslookup for me give

Non-authoritative answer:
Name:    www.bbc.net.uk
Addresses:  212.58.244.68
          212.58.244.69
Aliases:  www.bbc.co.uk

 

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mstokes
Beginner
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Message 6 of 8

Re: Infinity speed test variation between PCs

Thanks Chris.  Yes both are wired.  I noticed the routes were slightly different; one is the BT route, the other is Cable & Wireless (Vodafone).

 

I have retested with the IP address instead.  The slow PC is here:

 

Tracing route to bbc-vip113.telhc.bbc.co.uk [212.58.244.68]
over a maximum of 30 hops:

1 1 ms <1 ms <1 ms 192.168.1.1
2 * * * Request timed out.
3 * 7 ms 7 ms 31.55.186.193
4 7 ms 7 ms 6 ms 31.55.186.200
5 7 ms 7 ms 7 ms core3-hu0-16-0-3.
faraday.ukcore.bt.net [195.99.127.198]
6 7 ms 6 ms 7 ms peer2-
et-1-1-0.telehouse.ukcore.bt.net [213.121.193.163]
7 7 ms 7 ms 7 ms 194.74.65.42
8 * * * Request timed out.
9 * * * Request timed out.
10 7 ms 7 ms 7 ms ae0.er01.
telhc.bbc.co.uk [132.185.254.109]
11 * 8 ms 8 ms 132.185.255.148
12 7 ms 7 ms 6 ms
bbc-vip113.telhc.bbc.co.uk [212.58.244.68]

Trace complete.

 

The fast one is here:

 

Tracing route to bbc-vip113.telhc.bbc.co.uk [212.58.244.68]
over a maximum of 30 hops:

1 13 ms <1 ms <1 ms 192.168.1.1
2 * * * Request timed out.
3 * 6 ms 6 ms 31.55.186.193
4 7 ms 7 ms 7 ms 31.55.186.200
5 7 ms 7 ms 7 ms core3-hu0-16-0-3.
faraday.ukcore.bt.net [195.99.127.198]
6 7 ms 6 ms 6 ms peer2-
et-1-1-0.telehouse.ukcore.bt.net [213.121.193.163]
7 14 ms 7 ms 6 ms 194.74.65.42
8 * * * Request timed out.
9 * * * Request timed out.
10 8 ms 7 ms 7 ms ae0.er01.
telhc.bbc.co.uk [132.185.254.109]
11 8 ms 8 ms 8 ms 132.185.255.148
12 7 ms 7 ms 7 ms
bbc-vip113.telhc.bbc.co.uk [212.58.244.68]

Trace complete.

 

Very similar.  Of course this test does not involve a DNS look-up.

 

The Routing Table is very simple:

 

Key: C - connected, S - static, R - RIP, * - default, ~ - private
*            0.0.0.0/ 0.0.0.0          via 172.16.14.18      WAN1
S      86.136.145.57/ 255.255.255.255  via 86.136.145.57     WAN1
C~       192.168.1.0/ 255.255.255.0    directly connected    LAN1
*       172.16.14.18/ 255.255.255.255  via 172.16.14.18      WAN1

 

Interesting that the Gateway IP is an internal, 172.16.14.18

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ChrisFWood
Aspiring Contributor
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Message 7 of 8

Re: Infinity speed test variation between PCs

My guess is a stale dns cache on the iffy system hence the "ipconfig /flushdns" command, you can use nslookup to test the address it should be using. The BBC are using dns based load balancing by the looks of things try "nslookup www.bbc.co.uk 8.8.8.8" a few times to see what I mean, the results change every few times, if your PC got an answer that have you an iffy/overloaded route in BTs network that would explain the issue you are getting.

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mstokes
Beginner
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Message 8 of 8

Re: Infinity speed test variation between PCs

No, /flushdns made no change and /displaydns confirmed it is empty.

 

I have also flushed the DNS cache in the Draytek, although that is common to all PCs.

 

I see what you mean about the load sharing, but this is 100% consistent to one PC.  In fact when I first started investigating I was using an IP that didn't require a DNS look up.  And it was not bbc.co.uk so that is not relevant either.

 

I am still not completely convinced it is not a PC config thing.  But I have tried 100M full duplex and 100 half duplex rather than auto negotiate and whilst that does change the speed test result it does not resolve the issue.

 

I think I'll have to live with it for now until I get some more time.

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