Ethereal-users: [Ethereal-users] Router latency ( Long)
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From: "Bob DeBolt" <bob.debolt@xxxxxxxxxxxxxx>
Date: Tue, 8 Feb 2005 20:53:28 -0700
Greets To begin, forgive me if this has some rambling to it, a car crash a week ago has left my concentration rather off, but improving. I have been having an issues for a number of months now relating to the ISP of a client. The current situation is this: 1) Head office 2) Primary satellite office 3) Secondary Satellite office The satellite offices of the client installed VOIP and have had a ton of grief with it, not an uncommon story I'm sure. The VOIP system has dropped TOO many calls and is in the process of being replaced with the original PSTN. The head office and the primary satellite office are connected to the ISP through several miles of wireless. The traffic to and from the gateway of each of the primary offices own gateways check good with ICMP, TCP and UDP tests using hping, pchar, PingPlotter and several others that I forget as several months have past since last used. Repeated tests to each others gateway and to each of the internal IP addresses of the route to each other shows intermittent packet loss. The core router of the ISP is a Cisco 7200. The clients maximum throughput has not been an issue at any time. There is a 3 to 10 second "hesitation" across the network as the 7200 rereads the routing tables, processor is at %100 during the period, as told by the ISP. The ISP has stated that Cisco says this delay is normal for the routing table reload. Connections between the satellite offices will drop connections usually during the measured "hesitation", but not always. When the VOIP system was in place and several times during this hesitation, with active Citrix sessions, I observed no interruption in service or voice hesitation. During off hours the session drops have been as frequent as during main business hours. I have often been dropped while doing remote service via SSH to either office location at any time of day or night, through the IPSec tunnel or not. It does tend to die in early-mid afternoon more than any other time of day even though my clients bandwidth has lots of room left. The bandwidth at the primary satellite office is a shared radio between several other clients which resulted in some very serious over billing charges being made to my client. As the ISP has indicated to me and I have observed, the method employed by the ISP to diagnose the packet drop / latency is the Cisco routers "ping". The satellite offices are connected through OpenBSD 3.6 stable IPSec tunnels. The VOIP was NOT running through the IPSec Tunnels at any time, in fact with the VOIP system turned off there is no difference in the packet loss graphs as indicated by Ping Plotter ICMP mode. The Citrix sessions, whether or not running through the tunnels, traffic shows the same packet loss, session dropping characteristics. With only one Citrix client connected to the head office late at night via Internet there was packet loss whose timing matched the Citrix session. Each piece of equipment including the firewalls have been completely swapped out with the same results. I do not have direct access to the ISP equipment but have run a number of end to end tests with programs like pchar, hping etc., currently setting up a smokeping box to give an executive view of problems. Using pchar as the example, the tests, there has been a couple dozen of them have all shown very similar results as shown below. pchar to X.X.118.174 (X.X.118.174) using UDP/IPv4 Using raw socket input Packet size increments from 32 to 1500 by 32 46 test(s) per repetition 32 repetition(s) per hop 0: X.X.117.25 (X.X.117.25) Partial loss: 0 / 1472 (0%) Partial char: rtt = 3.699518 ms, (b = 0.004700 ms/B), r2 = 0.999498 stddev rtt = 0.012836, stddev b = 0.000016 Partial queueing: avg = 0.001132 ms (240 bytes) Hop char: rtt = 3.699518 ms, bw = 1701.956678 Kbps Hop queueing: avg = 0.001132 ms (240 bytes) 1: 172.18.8.94 (172.18.8.94) Partial loss: 2 / 1472 (0%) Partial char: rtt = 8.557417 ms, (b = 0.006275 ms/B), r2 = 0.987962 stddev rtt = 0.084370, stddev b = 0.000104 Partial queueing: avg = 0.031362 ms (19442 bytes) Hop char: rtt = 4.857899 ms, bw = 5081.703107 Kbps Hop queueing: avg = 0.030230 ms (19202 bytes) 2: 10.64.8.13 (10.64.8.13) Partial loss: 743 / 1472 (50%) Partial char: rtt = 10.569593 ms, (b = 0.006782 ms/B), r2 = 0.982938 stddev rtt = 0.108841, stddev b = 0.000135 Partial queueing: avg = 0.003006 ms (19442 bytes) Hop char: rtt = 2.012176 ms, bw = 15770.949211 Kbps Hop queueing: avg = -0.028356 ms (0 bytes) 3: 10.64.8.38 (10.64.8.38) Path length: 3 hops Path char: rtt = 10.569593 ms r2 = 0.982938 Path bottleneck: 1701.956678 Kbps Path pipe: 2248 bytes Path queueing: average = 0.003006 ms (19442 bytes) Start time: Thu Feb 3 08:41:37 2005 End time: Thu Feb 3 09:36:07 2005 I realize this is a large piece of pie to look at but my mind has gone numb working on this. I am open to suggestions as far as dealing with the ISP and a better tools selection / useage. It is the only client network I work on that has this issue and each of my clients use OpenBSD stable / IPSec. Coincidentally it is the only client using the ISP. I am at a point where I need to refocus the effort, I'm sure many of you know what I am talking about. Any suggestions / flames are welcome, I picked the Ethereal list to send this to as I have followed this list for sometime now and see by answers there is considerable experience. I am hoping that one of you can help me to kick start his process again. There is likely some very important info I'm missing here, hopefully my concentration will improve in another week or two. Bob
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