November 2010 - Test - lists.nanog.org

Re: Ciscos, BGP, L2TPV3 pseudowires and loopback Ips
by David Freedman 11 Nov '10

11 Nov '10

>> interface WAN1 (actually a gigether) >> ip unnumbered loopback0 (or no ip addr?) >> >That's not correct. Actually, was fixating on the fact that he has ethernet WAN and last I checked IOS doesn't have unnumbered-to-ethernet capability (well not true, recently they introduced unnumbered SVI support, don't know if it actually works on anything else) Dave. -- David Freedman Group Network Engineering david.freedman(a)uk.clara.net Tel +44 (0) 20 7685 8000 Claranet Group 21 Southampton Row London - WC1B 5HA - UK http://www.claranet.com Company Registration: 3152737 - Place of registration: England All the information contained within this electronic message from Claranet Ltd is covered by the disclaimer at http://www.claranet.co.uk/disclaimer

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Routing filters PA /31-/34
by Jack Bates 11 Nov '10

11 Nov '10

Anyone have any data on current and trends for routing /31-/34 of PA space via BGP? What type of isolation metrics might I be looking at today as well as in 1-2 years? Jack

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Thanks guys!
by Green, Timothy 11 Nov '10

11 Nov '10

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How do I change my email?
by Green, Tim R 11 Nov '10

11 Nov '10

I'm leaving the job attached to this email. This is my new email address timothy.green(a)mantech.com Thanks, Tim

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Emulating a cellular interface
by Saqib Ilyas 11 Nov '10

11 Nov '10

Greetings NANOGers A friend of mine is doing some testing where he wishes to emulate a cellular-like interfaces with random drops and all, out of an ethernet interface. Since we have plenty of network and system ops on the list, I thought we might have luck posting the question here. Is anyone aware of a simple tool to do this, other than rather involved configuration of iptables? Thanks and best regards -- Muhammad Saqib Ilyas PhD Student, Computer Science and Engineering Lahore University of Management Sciences

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re: AS path question.
by Nick Olsen 10 Nov '10

10 Nov '10

They are prepending routes. Looks like both 43022 are prepending, As well as 47359...Multiple times... They do this to make that route look "bad" so it comes in other transit they have. Nick Olsen Network Operations (855) FLSPEED x106 ---------------------------------------- From: "Greg Whynott" <Greg.Whynott(a)oicr.on.ca> Sent: Wednesday, November 10, 2010 3:23 PM To: "nanog(a)nanog.org list" <nanog(a)nanog.org> Subject: AS path question. Recently I adjusted the maxas-limit option on our router, logs started reporting routes being refused because the AS path is to long. seems to work as expected. when I looked at the logs I was a bit confused at what i was looking at... why is it there are multiple AS's in the path that appear to be the same AS? I expected an AS path comprised of mostly unique ASs. instead of this: 476330: Nov 10 14:55:07.247 EDT: %BGP-6-ASPATH: Long AS path 549 26677 6939 21011 43022 43022 43022 43022 43022 47359 47359 47359 47359 47359 47359 47359 47359 received from isp router: More than configured MAXAS-LIMIT i expected it would look more like: 476330: Nov 10 14:55:07.247 EDT: %BGP-6-ASPATH: Long AS path 549 26677 6939 21011 43022 47359 received from . .. . thanks for your time again, greg -- This message and any attachments may contain confidential and/or privileged information for the sole use of the intended recipient. Any review or distribution by anyone other than the person for whom it was originally intended is strictly prohibited. If you have received this message in error, please contact the sender and delete all copies. Opinions, conclusions or other information contained in this message may not be that of the organization.

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Re: RINA - scott whaps at the nanog hornets nest :-)
by Scott Weeks 10 Nov '10

10 Nov '10

--- dot(a)dotat.at wrote: From: Tony Finch <dot(a)dotat.at> On Mon, 8 Nov 2010, Scott Weeks wrote: > The mapping server idea that several proposals use do not appear to keep > the smartness at the edges, rather they seem try to make a smarter core > network. Is a DNS server core or edge? ILNP aims to use the DNS as its mapping service. -------------------------------------------------- DNS root name servers are at the 'core'. No? scott

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Re: AS path question.
by Scott Weeks 10 Nov '10

10 Nov '10

--- Valdis.Kletnieks(a)vt.edu wrote: From: Valdis.Kletnieks(a)vt.edu One has to wonder how many places are using the prepend-me-harder commands to do traffic engineering, and have absolutely no clue that their prepends are having the opposite effect because the prefix is being dropped entirely by some AS's. ------------------------------------------ Do you think (or is there evidence) that very many ASs use maxas-limit type commands? I have never used it and never had any problems... -------------------------------------- I suppose the exact same issue applies for those places that deaggregate in an attempt to to TE, and the de-aggregated prefixes get munched by somebody's prefix-length filter. ------------------------------------ Only if they're longer than a /24, though; yes? I imagine no one really filters shorter than a /24 these days. scott

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Re: GRE Tunnels and MPLS
by Rettke, Brian 10 Nov '10

10 Nov '10

This seems to be working now with the 'mls mpls tunnel-recir' command entered. There are some potential downsides, but this should get things up and running until I create the new backup tunnels (GRE over IPSec) on a connected router that is not MPLS-enabled. Thanks! Sincerely, Brian A . Rettke RHCT, CCDP, CCNP, CCIP Network Engineer, CableONE Internet Services ------------------------------ Message: 6 Date: Thu, 04 Nov 2010 16:49:55 -0400 From: Shimol Shah <shimshah(a)cisco.com> Subject: Re: GRE Tunnels and MPLS To: nanog(a)nanog.org Message-ID: <4CD31C73.80004(a)cisco.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Do you have recir enabled ? If not, good one to enable and check for status of issue. http://www.cisco.com/en/US/docs/ios/mpls/command/reference/mp_m1.html#wp101… "If you do not enable tunnel-MPLS recirculation, the IPv4 and IPv4-tunneled packets that need to be labeled (for example, the packets that are encapsulated with an MPLS header) will be corrupted when they are transmitted from the Cisco 7600 series router." Shimol On 11/4/10 4:00 PM, Rettke, Brian wrote: > Beginning work on our implementation of MPLS for the backbone network. I've run into difficulty with our GRE tunnels. The GRE Tunnel sits on our co-lo router (a Cisco 7600), and it uses a route-map to push our 10.x modem traffic to our DHCP servers. This is because the backbone is not complete and DHCP traffic needs to traverse the internet. What I have found is that when I enable basic MPLS on the co-location interfaces that head back to the individual systems, DHCP traffic still works, but ICMP and other 10.x traffic dies. There is also an intermittent problem with DHCP when it is enabled, where not all DISCOVERS are answered. I've tried everything I can think of, including adjusting MTU and TCP MSS. It only seems to impact when the co-location router has a GRE tunnel on one buffer, which it terminates, and then it has to encapsulate traffic with an MPLS tag before sending out of the other buffer. Theoretically, it should work, but I can't figure out if there is some prob lem with MPLS' interaction with the tunnel. Has anyone encountered something similar? > > Sincerely, > > Brian A . Rettke > RHCT, CCDP, CCNP, CCIP > Network Engineer, CableONE Internet Services > >

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AS path question.
by Greg Whynott 10 Nov '10

10 Nov '10

Recently I adjusted the maxas-limit option on our router, logs started reporting routes being refused because the AS path is to long. seems to work as expected. when I looked at the logs I was a bit confused at what i was looking at... why is it there are multiple AS's in the path that appear to be the same AS? I expected an AS path comprised of mostly unique ASs. instead of this: 476330: Nov 10 14:55:07.247 EDT: %BGP-6-ASPATH: Long AS path 549 26677 6939 21011 43022 43022 43022 43022 43022 47359 47359 47359 47359 47359 47359 47359 47359 received from isp router: More than configured MAXAS-LIMIT i expected it would look more like: 476330: Nov 10 14:55:07.247 EDT: %BGP-6-ASPATH: Long AS path 549 26677 6939 21011 43022 47359 received from … .. . thanks for your time again, greg -- This message and any attachments may contain confidential and/or privileged information for the sole use of the intended recipient. Any review or distribution by anyone other than the person for whom it was originally intended is strictly prohibited. If you have received this message in error, please contact the sender and delete all copies. Opinions, conclusions or other information contained in this message may not be that of the organization.

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