[56191] in North American Network Operators' Group
Re: ebgp-multihop
daemon@ATHENA.MIT.EDU (Jack Bates)
Thu Feb 27 18:52:51 2003
From: "Jack Bates" <jbates@brightok.net>
To: "Tim Rand" <randt@ohsu.edu>, <nanog@merit.edu>
Date: Thu, 27 Feb 2003 17:45:31 -0600
Errors-To: owner-nanog-outgoing@merit.edu
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From: Tim Rand=20
Hi -
I have searched the archives but have not found an answer to my =
question - is there any danger in using excessively high TTL values with =
ebgp-multihop? For example, neighbor x.x.x.x ebgp-multihop 255 - =
255 is generally much higher than needed, but is there any risk/danger =
?? Thanks in advance. - Tim
The number of hops in an ebgp-multihop scenario isn't usually the =
concern. When using ebgp sessions to null route baddies, the peer can be =
an unspecified number of hops away. I would consider 255 to be overkill, =
but not much harm. In normal routing, I would try to keep the hop count =
within 1 or 2. It's just a good practice. Remember, every router between =
the two sessions has to also know the route. Perhaps some of the older =
folks have some better tidbits of advice.
-Jack
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<DIV><B>From:</B> <A title=3Drandt@ohsu.edu =
href=3D"mailto:randt@ohsu.edu">Tim=20
Rand</A> </DIV>
<DIV><STRONG></STRONG> </DIV>
<DIV><STRONG>
<BLOCKQUOTE dir=3Dltr=20
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size=3D2></FONT><FONT=20
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<DIV>Hi -</DIV>
<DIV>I have searched the archives but have not found an answer to my =
question=20
- is there any danger in using excessively high TTL values with=20
ebgp-multihop? For example, neighbor x.x.x.x =
ebgp-multihop=20
255 - 255 is generally much higher than needed, but =
is there=20
any risk/danger ?? Thanks in advance. -=20
Tim</STRONG></DIV></BLOCKQUOTE></DIV>
<DIV><STRONG></STRONG> </DIV>
<DIV><FONT face=3DArial size=3D2>The number of hops in an ebgp-multihop =
scenario=20
isn't usually the concern. When using ebgp sessions to null route =
baddies, the=20
peer can be an unspecified number of hops away. I would consider 255 to =
be=20
overkill, but not much harm. In normal routing, I would try to keep the =
hop=20
count within 1 or 2. It's just a good practice. Remember, every router =
between=20
the two sessions has to also know the route. Perhaps some of the older =
folks=20
have some better tidbits of advice.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>-Jack</FONT></DIV></BODY></HTML>
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