Re: A new networking term - thoughts? [7:16668]
At 11:59 PM 8/21/01, Tony Medeiros wrote: I always thought split horizon was a non intuitive term anyway. iBGP or whatever. Some engineers come up with the strangest names for things. Split horizon implys there is a big tree that is obstructing my view of the sunset. :0 Is it a spanning tree? ;-) I like the term split horizon and agree with the idea of using it generically. I encourage the generic use of most terms so that people think about what they really mean. See a discussion we had earlier about distance vector, for example. For spanning tree, I like the way Radia Perlman puts it: The purpose of the spanning tree algorithm is to have bridges dynamically discover a subset of the topology that is loop-free (a tree) and yet has enough connectivity so that where physically possible, there is a path between every pair of LANs (the tree is spanning). I'm not sure I had ever thought about why the word spanning is in the phrase. And I would add to her description: A tree is a mathematical concept. A tree is a diagram or graph that branches from a single stem without forming loops or polygons. A lot of people learn these terms without understanding them. And, back to the subject, I think split horizon can be used in this situation, even though it's a bit different and the horizons aren't quite the same. Priscilla (wishing she was looking over the Hawaiian horizon about now. ;-) Tony M. (Split personnality) - Original Message - From: Chuck Larrieu To: Sent: Tuesday, August 21, 2001 8:13 PM Subject: RE: A new networking term - thoughts? [7:16668] I thought I was fairly careful in stating that with iBGP split-horizon, an iBGP router will not advertise a route to the same AS from which it receives the route. This covers the interface issue. Chuck whose mama didn't raise no fool, and whose lawyer wife has taught him the hard way about wording things ;- -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Ole Drews Jensen Sent: Tuesday, August 21, 2001 8:52 AM To: [EMAIL PROTECTED] Subject: RE: A new networking term - thoughts? [7:16668] Chuck, I think there's a difference here. Split Horizon as you say, does not advertise a route back out the interface that it received it on, but the iBGP does not only not propagate a route learned from other iBGP out the receiving interface, but it does not propagate it out any interfaces unless it has been setup as a cluster server. If you would name this, it would probably be something like iBGP horizon :-) Just my 0010 cents. Ole ~~~ Ole Drews Jensen Systems Network Manager CCNA, MCSE, MCP+I RWR Enterprises, Inc. [EMAIL PROTECTED] ~~~ http://www.RouterChief.com ~~~ NEED A JOB ??? http://www.oledrews.com/job ~~~ -Original Message- From: Chuck Larrieu [mailto:[EMAIL PROTECTED]] Sent: Tuesday, August 21, 2001 10:29 AM To: [EMAIL PROTECTED] Subject: A new networking term - thoughts? [7:16668] As a result of an off-list conversation, I came across the following networking term: iBGP split horizon my first reaction was a sarcastic remark about never having come across the term in the RFC's. but then I got to thinking about it, and I now see this as a descriptive and quite useful term. recall that distance vector protocols are subject to the rule of split horizon. they do not advertise a route back out the interface that they received that particular route. one of the gotchas of iBGP is the fact that iBGP routers do not propagate routes learned from one iBGP neighbor to other iBGP neighbors. hence the requirement for iBGP full mesh. so why not call this iBGP split horizon? and define it as follows: an iBGP router will not advertise a route back out the same AS from which it learned the route? does this make sense? worth letting this one join the lexicon of networking terminology? Chuck Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=16851t=16668 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: A new networking term - thoughts? [7:16668]
Since we are talking about new networking terms you coined one the other day Priscilla. It was in the splitting the group string. You described people coming on this list, asking horribly worded questions, that were probably quickly brain-dumped to a palm pilot then regurgitated here. This is after a booming failure. So that is a new networking/list term. Palm-Pilot English. And the coin is yours. Don P.S. That busted me up!! - Original Message - From: Priscilla Oppenheimer To: Sent: Wednesday, August 22, 2001 10:29 AM Subject: Re: A new networking term - thoughts? [7:16668] At 11:59 PM 8/21/01, Tony Medeiros wrote: I always thought split horizon was a non intuitive term anyway. iBGP or whatever. Some engineers come up with the strangest names for things. Split horizon implys there is a big tree that is obstructing my view of the sunset. :0 Is it a spanning tree? ;-) I like the term split horizon and agree with the idea of using it generically. I encourage the generic use of most terms so that people think about what they really mean. See a discussion we had earlier about distance vector, for example. For spanning tree, I like the way Radia Perlman puts it: The purpose of the spanning tree algorithm is to have bridges dynamically discover a subset of the topology that is loop-free (a tree) and yet has enough connectivity so that where physically possible, there is a path between every pair of LANs (the tree is spanning). I'm not sure I had ever thought about why the word spanning is in the phrase. And I would add to her description: A tree is a mathematical concept. A tree is a diagram or graph that branches from a single stem without forming loops or polygons. A lot of people learn these terms without understanding them. And, back to the subject, I think split horizon can be used in this situation, even though it's a bit different and the horizons aren't quite the same. Priscilla (wishing she was looking over the Hawaiian horizon about now. ;-) Tony M. (Split personnality) - Original Message - From: Chuck Larrieu To: Sent: Tuesday, August 21, 2001 8:13 PM Subject: RE: A new networking term - thoughts? [7:16668] I thought I was fairly careful in stating that with iBGP split-horizon, an iBGP router will not advertise a route to the same AS from which it receives the route. This covers the interface issue. Chuck whose mama didn't raise no fool, and whose lawyer wife has taught him the hard way about wording things ;- -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Ole Drews Jensen Sent: Tuesday, August 21, 2001 8:52 AM To: [EMAIL PROTECTED] Subject: RE: A new networking term - thoughts? [7:16668] Chuck, I think there's a difference here. Split Horizon as you say, does not advertise a route back out the interface that it received it on, but the iBGP does not only not propagate a route learned from other iBGP out the receiving interface, but it does not propagate it out any interfaces unless it has been setup as a cluster server. If you would name this, it would probably be something like iBGP horizon :-) Just my 0010 cents. Ole ~~~ Ole Drews Jensen Systems Network Manager CCNA, MCSE, MCP+I RWR Enterprises, Inc. [EMAIL PROTECTED] ~~~ http://www.RouterChief.com ~~~ NEED A JOB ??? http://www.oledrews.com/job ~~~ -Original Message- From: Chuck Larrieu [mailto:[EMAIL PROTECTED]] Sent: Tuesday, August 21, 2001 10:29 AM To: [EMAIL PROTECTED] Subject: A new networking term - thoughts? [7:16668] As a result of an off-list conversation, I came across the following networking term: iBGP split horizon my first reaction was a sarcastic remark about never having come across the term in the RFC's. but then I got to thinking about it, and I now see this as a descriptive and quite useful term. recall that distance vector protocols are subject to the rule of split horizon. they do not advertise a route back out the interface that they received that particular route. one of the gotchas of iBGP is the fact that iBGP routers do not propagate routes learned from one iBGP neighbor to other iBGP neighbors. hence the requirement for iBGP full mesh. so why not call this iBGP split horizon? and define it as follows: an iBGP router will not advertise a route back out the same AS from which it learned the route? does this make sense? worth letting this one join the lexicon of networking terminology? Chuck Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f
A new networking term - thoughts? [7:16668]
As a result of an off-list conversation, I came across the following networking term: iBGP split horizon my first reaction was a sarcastic remark about never having come across the term in the RFC's. but then I got to thinking about it, and I now see this as a descriptive and quite useful term. recall that distance vector protocols are subject to the rule of split horizon. they do not advertise a route back out the interface that they received that particular route. one of the gotchas of iBGP is the fact that iBGP routers do not propagate routes learned from one iBGP neighbor to other iBGP neighbors. hence the requirement for iBGP full mesh. so why not call this iBGP split horizon? and define it as follows: an iBGP router will not advertise a route back out the same AS from which it learned the route? does this make sense? worth letting this one join the lexicon of networking terminology? Chuck Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=16668t=16668 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: A new networking term - thoughts? [7:16668]
Chuck, I think there's a difference here. Split Horizon as you say, does not advertise a route back out the interface that it received it on, but the iBGP does not only not propagate a route learned from other iBGP out the receiving interface, but it does not propagate it out any interfaces unless it has been setup as a cluster server. If you would name this, it would probably be something like iBGP horizon :-) Just my 0010 cents. Ole ~~~ Ole Drews Jensen Systems Network Manager CCNA, MCSE, MCP+I RWR Enterprises, Inc. [EMAIL PROTECTED] ~~~ http://www.RouterChief.com ~~~ NEED A JOB ??? http://www.oledrews.com/job ~~~ -Original Message- From: Chuck Larrieu [mailto:[EMAIL PROTECTED]] Sent: Tuesday, August 21, 2001 10:29 AM To: [EMAIL PROTECTED] Subject: A new networking term - thoughts? [7:16668] As a result of an off-list conversation, I came across the following networking term: iBGP split horizon my first reaction was a sarcastic remark about never having come across the term in the RFC's. but then I got to thinking about it, and I now see this as a descriptive and quite useful term. recall that distance vector protocols are subject to the rule of split horizon. they do not advertise a route back out the interface that they received that particular route. one of the gotchas of iBGP is the fact that iBGP routers do not propagate routes learned from one iBGP neighbor to other iBGP neighbors. hence the requirement for iBGP full mesh. so why not call this iBGP split horizon? and define it as follows: an iBGP router will not advertise a route back out the same AS from which it learned the route? does this make sense? worth letting this one join the lexicon of networking terminology? Chuck Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=16678t=16668 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: A new networking term - thoughts? [7:16668]
Interesting, But traditional split-horizon seems to be concerned with the interface the routes came in and went out on, whereas with iBGP the routes are not passed even if they come in one interface, but are being sent out another, Its more of a peer level than an interface level. Brian On Tue, 21 Aug 2001, Chuck Larrieu wrote: As a result of an off-list conversation, I came across the following networking term: iBGP split horizon my first reaction was a sarcastic remark about never having come across the term in the RFC's. but then I got to thinking about it, and I now see this as a descriptive and quite useful term. recall that distance vector protocols are subject to the rule of split horizon. they do not advertise a route back out the interface that they received that particular route. one of the gotchas of iBGP is the fact that iBGP routers do not propagate routes learned from one iBGP neighbor to other iBGP neighbors. hence the requirement for iBGP full mesh. so why not call this iBGP split horizon? and define it as follows: an iBGP router will not advertise a route back out the same AS from which it learned the route? does this make sense? worth letting this one join the lexicon of networking terminology? Chuck I'm buying / selling used CISCO gear!! email me for a quote Brian Feeny, CCIE #8036 Scarlett Parria [EMAIL PROTECTED] [EMAIL PROTECTED] 318-213-4709 318-213-4701 Netjam, LLC http://www.netjam.net 333 Texas St. VISA/MC/AMEX/COD Suite 140130 day warranty Shreveport, LA 71101 Cisco Channel Partner toll free: 866-2NETJAM phone: 318-212-0245 fax: 318-212-0246 Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=16680t=16668 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: A new networking term - thoughts? [7:16668]
I've actually heard that term used before, and I think it *may* have been in one of Howard's books or CertificationZone papers. Maybe not, I'm sure he'll correct me. I do know that I've heard the term split horizon in this context before. I agree that we should probably use it more often. A slight modification might be that a BGP speaker will ignore updates that include its own ASN in the path. I don't know if that still qualifies as split horizon since it's the receiver of the route that is disallowing the update, not the sender (as in the case of split horizon in other protocols.)Still, the end result is the same and I think it applies. John Chuck Larrieu 8/21/01 9:29:20 AM As a result of an off-list conversation, I came across the following networking term: iBGP split horizon my first reaction was a sarcastic remark about never having come across the term in the RFC's. but then I got to thinking about it, and I now see this as a descriptive and quite useful term. recall that distance vector protocols are subject to the rule of split horizon. they do not advertise a route back out the interface that they received that particular route. one of the gotchas of iBGP is the fact that iBGP routers do not propagate routes learned from one iBGP neighbor to other iBGP neighbors. hence the requirement for iBGP full mesh. so why not call this iBGP split horizon? and define it as follows: an iBGP router will not advertise a route back out the same AS from which it learned the route? does this make sense? worth letting this one join the lexicon of networking terminology? Chuck Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=16686t=16668 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: A new networking term - thoughts? [7:16668]
I thought I was fairly careful in stating that with iBGP split-horizon, an iBGP router will not advertise a route to the same AS from which it receives the route. This covers the interface issue. Chuck whose mama didn't raise no fool, and whose lawyer wife has taught him the hard way about wording things ;- -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Ole Drews Jensen Sent: Tuesday, August 21, 2001 8:52 AM To: [EMAIL PROTECTED] Subject: RE: A new networking term - thoughts? [7:16668] Chuck, I think there's a difference here. Split Horizon as you say, does not advertise a route back out the interface that it received it on, but the iBGP does not only not propagate a route learned from other iBGP out the receiving interface, but it does not propagate it out any interfaces unless it has been setup as a cluster server. If you would name this, it would probably be something like iBGP horizon :-) Just my 0010 cents. Ole ~~~ Ole Drews Jensen Systems Network Manager CCNA, MCSE, MCP+I RWR Enterprises, Inc. [EMAIL PROTECTED] ~~~ http://www.RouterChief.com ~~~ NEED A JOB ??? http://www.oledrews.com/job ~~~ -Original Message- From: Chuck Larrieu [mailto:[EMAIL PROTECTED]] Sent: Tuesday, August 21, 2001 10:29 AM To: [EMAIL PROTECTED] Subject: A new networking term - thoughts? [7:16668] As a result of an off-list conversation, I came across the following networking term: iBGP split horizon my first reaction was a sarcastic remark about never having come across the term in the RFC's. but then I got to thinking about it, and I now see this as a descriptive and quite useful term. recall that distance vector protocols are subject to the rule of split horizon. they do not advertise a route back out the interface that they received that particular route. one of the gotchas of iBGP is the fact that iBGP routers do not propagate routes learned from one iBGP neighbor to other iBGP neighbors. hence the requirement for iBGP full mesh. so why not call this iBGP split horizon? and define it as follows: an iBGP router will not advertise a route back out the same AS from which it learned the route? does this make sense? worth letting this one join the lexicon of networking terminology? Chuck Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=16757t=16668 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: A new networking term - thoughts? [7:16668]
I'm told that the term appears in the Cisco BSCN course material. Chuck -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of John Neiberger Sent: Tuesday, August 21, 2001 9:35 AM To: [EMAIL PROTECTED] Subject: Re: A new networking term - thoughts? [7:16668] I've actually heard that term used before, and I think it *may* have been in one of Howard's books or CertificationZone papers. Maybe not, I'm sure he'll correct me. I do know that I've heard the term split horizon in this context before. I agree that we should probably use it more often. A slight modification might be that a BGP speaker will ignore updates that include its own ASN in the path. I don't know if that still qualifies as split horizon since it's the receiver of the route that is disallowing the update, not the sender (as in the case of split horizon in other protocols.)Still, the end result is the same and I think it applies. John Chuck Larrieu 8/21/01 9:29:20 AM As a result of an off-list conversation, I came across the following networking term: iBGP split horizon my first reaction was a sarcastic remark about never having come across the term in the RFC's. but then I got to thinking about it, and I now see this as a descriptive and quite useful term. recall that distance vector protocols are subject to the rule of split horizon. they do not advertise a route back out the interface that they received that particular route. one of the gotchas of iBGP is the fact that iBGP routers do not propagate routes learned from one iBGP neighbor to other iBGP neighbors. hence the requirement for iBGP full mesh. so why not call this iBGP split horizon? and define it as follows: an iBGP router will not advertise a route back out the same AS from which it learned the route? does this make sense? worth letting this one join the lexicon of networking terminology? Chuck Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=16760t=16668 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: A new networking term - thoughts? [7:16668]
I always thought split horizon was a non intuitive term anyway. iBGP or whatever. Some engineers come up with the strangest names for things. Split horizon implys there is a big tree that is obstructing my view of the sunset. :0 Tony M. (Split personnality) - Original Message - From: Chuck Larrieu To: Sent: Tuesday, August 21, 2001 8:13 PM Subject: RE: A new networking term - thoughts? [7:16668] I thought I was fairly careful in stating that with iBGP split-horizon, an iBGP router will not advertise a route to the same AS from which it receives the route. This covers the interface issue. Chuck whose mama didn't raise no fool, and whose lawyer wife has taught him the hard way about wording things ;- -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Ole Drews Jensen Sent: Tuesday, August 21, 2001 8:52 AM To: [EMAIL PROTECTED] Subject: RE: A new networking term - thoughts? [7:16668] Chuck, I think there's a difference here. Split Horizon as you say, does not advertise a route back out the interface that it received it on, but the iBGP does not only not propagate a route learned from other iBGP out the receiving interface, but it does not propagate it out any interfaces unless it has been setup as a cluster server. If you would name this, it would probably be something like iBGP horizon :-) Just my 0010 cents. Ole ~~~ Ole Drews Jensen Systems Network Manager CCNA, MCSE, MCP+I RWR Enterprises, Inc. [EMAIL PROTECTED] ~~~ http://www.RouterChief.com ~~~ NEED A JOB ??? http://www.oledrews.com/job ~~~ -Original Message- From: Chuck Larrieu [mailto:[EMAIL PROTECTED]] Sent: Tuesday, August 21, 2001 10:29 AM To: [EMAIL PROTECTED] Subject: A new networking term - thoughts? [7:16668] As a result of an off-list conversation, I came across the following networking term: iBGP split horizon my first reaction was a sarcastic remark about never having come across the term in the RFC's. but then I got to thinking about it, and I now see this as a descriptive and quite useful term. recall that distance vector protocols are subject to the rule of split horizon. they do not advertise a route back out the interface that they received that particular route. one of the gotchas of iBGP is the fact that iBGP routers do not propagate routes learned from one iBGP neighbor to other iBGP neighbors. hence the requirement for iBGP full mesh. so why not call this iBGP split horizon? and define it as follows: an iBGP router will not advertise a route back out the same AS from which it learned the route? does this make sense? worth letting this one join the lexicon of networking terminology? Chuck Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=16765t=16668 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: A new networking term - thoughts? [7:16668]
You were, you were, but that was not my point. My point was that Split Horizon 'splits' the 'horizon' the routing update came from, from the outgoing 'horizon' the update is forwarded out through. On iBGP, it doesn't propagate it out to any (unless again it's a cluster server) so the term Split Horizon would be incorrect to use here. I would rather call it No Horizon, or something similar but different than S.H. Ole, who likes to play the blues on his Fender Stratocaster :-) Ole Drews Jensen Systems Network Manager CCNA, MCSE, MCP+I RWR Enterprises, Inc. [EMAIL PROTECTED] http://www.RouterChief.com NEED A JOB ??? http://www.oledrews.com/job -Original Message- From: Chuck Larrieu [mailto:[EMAIL PROTECTED]] Sent: Tuesday, August 21, 2001 9:57 PM To: Ole Drews Jensen; [EMAIL PROTECTED] Subject: RE: A new networking term - thoughts? [7:16668] I thought I was fairly careful in stating that with iBGP split-horizon, an iBGP router will not advertise a route to the same AS from which it receives the route. This covers the interface issue. Chuck whose mama didn't raise no fool, and whose lawyer wife has taught him the hard way about wording things ;- -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Ole Drews Jensen Sent: Tuesday, August 21, 2001 8:52 AM To: [EMAIL PROTECTED] Subject: RE: A new networking term - thoughts? [7:16668] Chuck, I think there's a difference here. Split Horizon as you say, does not advertise a route back out the interface that it received it on, but the iBGP does not only not propagate a route learned from other iBGP out the receiving interface, but it does not propagate it out any interfaces unless it has been setup as a cluster server. If you would name this, it would probably be something like iBGP horizon :-) Just my 0010 cents. Ole ~~~ Ole Drews Jensen Systems Network Manager CCNA, MCSE, MCP+I RWR Enterprises, Inc. [EMAIL PROTECTED] ~~~ http://www.RouterChief.com ~~~ NEED A JOB ??? http://www.oledrews.com/job ~~~ -Original Message- From: Chuck Larrieu [mailto:[EMAIL PROTECTED]] Sent: Tuesday, August 21, 2001 10:29 AM To: [EMAIL PROTECTED] Subject: A new networking term - thoughts? [7:16668] As a result of an off-list conversation, I came across the following networking term: iBGP split horizon my first reaction was a sarcastic remark about never having come across the term in the RFC's. but then I got to thinking about it, and I now see this as a descriptive and quite useful term. recall that distance vector protocols are subject to the rule of split horizon. they do not advertise a route back out the interface that they received that particular route. one of the gotchas of iBGP is the fact that iBGP routers do not propagate routes learned from one iBGP neighbor to other iBGP neighbors. hence the requirement for iBGP full mesh. so why not call this iBGP split horizon? and define it as follows: an iBGP router will not advertise a route back out the same AS from which it learned the route? does this make sense? worth letting this one join the lexicon of networking terminology? Chuck Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=16766t=16668 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
