On Tue, 12 Aug 2008, Jon Lewis wrote:
What would happen if you pinged the Ocala router such that the TTL was 1 when travelling over the DS3? From your traceroute it seems it travelled two IP hops that did not send ICMP error messages, but it might just be that the ICMP errors from the Ocala router are arriving first.
Based on where the dupes are coming from, I assume pinging across the DS3 with TTL tuned to expire at the Ocala side would result in TTL exceeded messages from both Ocala and the Sprint router where the packets are injected into Sprint's network. It doesn't look as if IOS gives the option to set TTL on ping...so I'd try this from a Linux machine in our data center.
I just went ahead and "re-broke" the circuit for a bit by turning it back to hdlc to see if the issue is still there and to run some additional tests. Someone is still cross connecting our Orlando->Ocala traffic over to Sprint. I did your suggested ping with short TTL and the result was close to what I expected. $ traceroute ocalflxa-br-1 traceroute to ocalflxa-br-1.atlantic.net (209.208.6.229), 30 hops max, 38 byte packets 1 209.208.25.165 (209.208.25.165) 0.539 ms 0.426 ms 0.388 ms 2 69.28.72.162 (69.28.72.162) 0.246 ms 0.351 ms 0.223 ms 3 andc-br-3-f2-0 (209.208.9.138) 0.559 ms 0.435 ms 0.471 ms 4 ocalflxa-br-1-s1-0 (209.208.112.98) 2.735 ms * 2.656 ms So, I need a TTL of 4 to get there from this machine. $ ping -t4 ocalflxa-br-1 PING ocalflxa-br-1.atlantic.net (209.208.6.229) 56(84) bytes of data. 64 bytes from ocalflxa-br-1.atlantic.net (209.208.6.229): icmp_seq=0 ttl=252 time=2.68 ms 64 bytes from ocalflxa-br-1.atlantic.net (209.208.6.229): icmp_seq=1 ttl=252 time=2.72 ms 64 bytes from ocalflxa-br-1.atlantic.net (209.208.6.229): icmp_seq=2 ttl=252 time=2.88 ms Decrease ttl by one, and I get the expected ttl exceeded from the Orlando side of the circuit. $ ping -t 3 ocalflxa-br-1 PING ocalflxa-br-1.atlantic.net (209.208.6.229) 56(84) bytes of data.
From andc-br-3-f2-0.atlantic.net (209.208.9.138) icmp_seq=0 Time to live exceeded
Now, here's a mild surprise. You'll notice that in the above -t4 trace, I didn't hear back from Sprint. $ ping -t 5 ocalflxa-br-1 PING ocalflxa-br-1.atlantic.net (209.208.6.229) 56(84) bytes of data. 64 bytes from ocalflxa-br-1.atlantic.net (209.208.6.229): icmp_seq=0 ttl=252 time=2.89 ms 64 bytes from ocalflxa-br-1.atlantic.net (209.208.6.229): icmp_seq=1 ttl=252 time=3.10 ms 64 bytes from ocalflxa-br-1.atlantic.net (209.208.6.229): icmp_seq=2 ttl=252 time=2.97 ms hmm...still no ttl exceeded from Sprint? $ ping -t 6 ocalflxa-br-1 PING ocalflxa-br-1.atlantic.net (209.208.6.229) 56(84) bytes of data. 64 bytes from ocalflxa-br-1.atlantic.net (209.208.6.229): icmp_seq=0 ttl=252 time=2.95 ms
From sl-crs2-dc-0-5-3-0.sprintlink.net (144.232.19.93) icmp_seq=0 Time to live exceeded 64 bytes from ocalflxa-br-1.atlantic.net (209.208.6.229): icmp_seq=1 ttl=252 time=2.78 ms From sl-crs2-dc-0-5-3-0.sprintlink.net (144.232.19.93) icmp_seq=1 Time to live exceeded
$ ping -t 7 ocalflxa-br-1 PING ocalflxa-br-1.atlantic.net (209.208.6.229) 56(84) bytes of data. 64 bytes from ocalflxa-br-1.atlantic.net (209.208.6.229): icmp_seq=0 ttl=252 time=2.88 ms
From sl-st20-ash-9-0-0.sprintlink.net (144.232.18.228) icmp_seq=0 Time to live exceeded 64 bytes from ocalflxa-br-1.atlantic.net (209.208.6.229): icmp_seq=1 ttl=252 time=2.84 ms From sl-st20-ash-9-0-0.sprintlink.net (144.232.18.228) icmp_seq=1 Time to live exceeded
From the traces I've seen, it seems if the first Sprint hop is sl-bb20-dc,
Is it just coincidence that there are 2 private IP hops in some traceroutes between us and Sprint? i.e. Look at this trace from cogent: Tracing the route to 209.208.33.1 1 fa0-8.na01.b005944-0.dca01.atlas.cogentco.com (66.250.56.189) 0 msec 4 msec 4 msec 2 gi3-9.3507.core01.dca01.atlas.cogentco.com (66.28.67.225) 160 msec 4 msec 8 msec 3 te3-1.ccr02.dca01.atlas.cogentco.com (154.54.3.158) 0 msec 0 msec 4 msec 4 vl3493.mpd01.dca02.atlas.cogentco.com (154.54.7.230) 28 msec 4 msec te4-1.mpd01.dca02.atlas.cogentco.com (154.54.2.182) 52 msec 5 vl3494.mpd01.iad01.atlas.cogentco.com (154.54.5.42) 4 msec 4 msec vl3497.mpd01.iad01.atlas.cogentco.com (154.54.5.66) 4 msec 6 timewarner.iad01.atlas.cogentco.com (154.54.13.250) 4 msec peer-01-ge-3-1-2-13.asbn.twtelecom.net (66.192.252.217) 4 msec 12 msec 7 66-194-200-202.static.twtelecom.net (66.194.200.202) 28 msec 28 msec 32 msec 8 66-194-200-202.static.twtelecom.net (66.194.200.202) 32 msec 32 msec 28 msec 9 andc-br-3-f2-0.atlantic.net (209.208.9.138) 32 msec 32 msec 32 msec 10 172.22.122.1 32 msec 32 msec 32 msec 11 10.247.28.205 32 msec 32 msec 32 msec 12 sl-crs2-dc-0-5-3-0.sprintlink.net (144.232.19.93) 32 msec 32 msec 28 msec 13 sl-st20-ash-9-0-0.sprintlink.net (144.232.18.228) 28 msec 32 msec 32 msec 14 te-10-1-0.edge2.Washington4.level3.net (4.68.63.209) 32 msec 32 msec 28 msec 15 vlan79.csw2.Washington1.Level3.net (4.68.17.126) 28 msec vlan89.csw3.Washington1.Level3.net (4.68.17.190) 32 msec vlan79.csw2.Washington1.Level3.net (4.68.17.126) 40 msec 16 ae-81-81.ebr1.Washington1.Level3.net (4.69.134.137) 28 msec ae-61-61.ebr1.Washington1.Level3.net (4.69.134.129) 28 msec ae-71-71.ebr1.Washington1.Level3.net (4.69.134.133) 32 msec 17 ae-2.ebr3.Atlanta2.Level3.net (4.69.132.85) 48 msec 48 msec 56 msec 18 ae-61-60.ebr1.Atlanta2.Level3.net (4.69.138.2) 44 msec 48 msec ae-71-70.ebr1.Atlanta2.Level3.net (4.69.138.18) 52 msec 19 ae-1-8.bar1.Orlando1.Level3.net (4.69.137.149) 56 msec 104 msec 56 msec 20 ae-6-6.car1.Orlando1.Level3.net (4.69.133.77) 52 msec 52 msec 56 msec 21 unknown.Level3.net (63.209.98.66) 52 msec 52 msec 56 msec 22 andc-br-3-f2-0.atlantic.net (209.208.9.138) 52 msec 52 msec 56 msec 23 172.22.122.1 52 msec 56 msec 52 msec 24 10.247.28.205 52 msec 52 msec 56 msec 25 sl-crs2-dc-0-5-3-0.sprintlink.net (144.232.19.93) 52 msec 56 msec 52 msec 26 sl-st20-ash-9-0-0.sprintlink.net (144.232.18.228) 56 msec 56 msec 56 msec 27 te-10-1-0.edge2.Washington4.level3.net (4.68.63.209) 52 msec 52 msec 52 msec 28 vlan99.csw4.Washington1.Level3.net (4.68.17.254) 52 msec vlan69.csw1.Washington1.Level3.net (4.68.17.62) 56 msec vlan89.csw3.Washington1.Level3.net (4.68.17.190) 56 msec 29 ae-71-71.ebr1.Washington1.Level3.net (4.69.134.133) 64 msec ae-61-61.ebr1.Washington1.Level3.net (4.69.134.129) 52 msec 56 msec 30 ae-2.ebr3.Atlanta2.Level3.net (4.69.132.85) 76 msec 72 msec 72 msec I've seen the 172.22.122.1 & 10.247.28.205 hops before. They occasionally show up in traces when the traffic is jumping over to Sprint. Sometimes they don't show up though. i.e. Tracing from my house: traceroute to 209.208.33.1 (209.208.33.1), 30 hops max, 40 byte packets 1 172.31.0.1 (172.31.0.1) 0.336 ms 0.272 ms 0.268 ms 2 10.210.160.1 (10.210.160.1) 10.109 ms 11.719 ms 14.265 ms 3 gig7-0-4-101.orldflaabv-rtr1.cfl.rr.com (24.95.232.100) 15.302 ms 15.324 ms 16.687 ms 4 198.228.95.24.cfl.res.rr.com (24.95.228.198) 16.688 ms 18.812 ms 18.816 ms 5 te-3-3.car1.Orlando1.Level3.net (4.79.116.145) 20.084 ms 19.946 ms te-3-1.car1.Orlando1.Level3.net (4.79.116.137) 21.328 ms 6 unknown.Level3.net (63.209.98.66) 19.900 ms 14.714 ms 14.689 ms 7 andc-br-3-f2-0.atlantic.net (209.208.9.138) 104.058 ms 11.932 ms 13.584 ms 8 ocalflxa-br-1-s1-0.atlantic.net (209.208.112.98) 15.872 ms 15.886 ms 17.238 ms 9 * * * 10 sl-bb20-dc-6-0-0.sprintlink.net (144.232.8.174) 41.277 ms 41.964 ms 41.955 ms 11 sl-st20-ash-10-0.sprintlink.net (144.232.20.152) 43.360 ms 44.578 ms 35.635 ms 12 te-10-1-0.edge2.Washington4.level3.net (4.68.63.209) 37.035 ms 37.062 ms 33.185 ms 13 vlan89.csw3.Washington1.Level3.net (4.68.17.190) 44.060 ms 44.057 ms vlan99.csw4.Washington1.Level3.net (4.68.17.254) 39.603 ms 14 ae-81-81.ebr1.Washington1.Level3.net (4.69.134.137) 38.123 ms ae-91-91.ebr1.Washington1.Level3.net (4.69.134.141) 39.546 ms ae-71-71.ebr1.Washington1.Level3.net (4.69.134.133) 38.115 ms 15 ae-2.ebr3.Atlanta2.Level3.net (4.69.132.85) 46.284 ms 46.275 ms 46.274 ms 16 ae-71-70.ebr1.Atlanta2.Level3.net (4.69.138.18) 52.523 ms ae-61-60.ebr1.Atlanta2.Level3.net (4.69.138.2) 53.338 ms ae-71-70.ebr1.Atlanta2.Level3.net (4.69.138.18) 53.299 ms 17 ae-1-8.bar1.Orlando1.Level3.net (4.69.137.149) 34.964 ms 39.582 ms 38.088 ms 18 ae-6-6.car1.Orlando1.Level3.net (4.69.133.77) 36.701 ms 38.144 ms 36.949 ms 19 unknown.Level3.net (63.209.98.66) 36.902 ms 37.750 ms 37.717 ms 20 andc-br-3-f2-0.atlantic.net (209.208.9.138) 37.729 ms 35.812 ms 35.048 ms 21 ocalflxa-br-1-s1-0.atlantic.net (209.208.112.98) 37.485 ms 37.601 ms 36.495 ms 22 * * * 23 sl-bb20-dc-6-0-0.sprintlink.net (144.232.8.174) 56.459 ms 56.449 ms 57.709 ms 24 sl-st20-ash-10-0.sprintlink.net (144.232.20.152) 57.694 ms 57.692 ms 60.243 ms 25 te-10-1-0.edge2.Washington4.level3.net (4.68.63.209) 103.257 ms 100.829 ms 82.571 ms 26 vlan99.csw4.Washington1.Level3.net (4.68.17.254) 70.401 ms vlan89.csw3.Washington1.Level3.net (4.68.17.190) 69.262 ms vlan99.csw4.Washington1.Level3.net (4.68.17.254) 82.700 ms 27 ae-81-81.ebr1.Washington1.Level3.net (4.69.134.137) 74.132 ms ae-61-61.ebr1.Washington1.Level3.net (4.69.134.129) 74.135 ms ae-81-81.ebr1.Washington1.Level3.net (4.69.134.137) 75.540 ms 28 ae-2.ebr3.Atlanta2.Level3.net (4.69.132.85) 58.656 ms 60.838 ms 54.346 ms 29 ae-71-70.ebr1.Atlanta2.Level3.net (4.69.138.18) 59.323 ms ae-61-60.ebr1.Atlanta2.Level3.net (4.69.138.2) 59.336 ms ae-71-70.ebr1.Atlanta2.Level3.net (4.69.138.18) 63.323 ms 30 ae-1-8.bar1.Orlando1.Level3.net (4.69.137.149) 127.652 ms 57.884 ms 57.851 ms the private IP hops don't show up. If the first Sprint hop is sl-crs2-dc, then the private IP hops are there. I wonder if anyone from Sprint can shed some light on that? Unfortunately, the Sprint engineer I intitially made contact with who was helpful and seemed curious about the issue seems to have vanished and isn't returning my calls or emails. Anyone else from Sprintlink care to play? ---------------------------------------------------------------------- Jon Lewis | I route Senior Network Engineer | therefore you are Atlantic Net | _________ http://www.lewis.org/~jlewis/pgp for PGP public key_________