Re: RFC5798

Stephen Nadas <[email protected]> Thu, 14 Oct 2010 12:10:17 -0400
Newsgroups gmane.ietf.vrrp
Message-ID <450AE4BEC513614F96969DDA34F35934149DC427BD@EUSAACMS0701.eamcs.ericsson.se> 
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IMO better to ask VRRP list than me, individually,
Regards,
Steve

________________________________
From: Carl Petersen [mailto:[email protected]]
Sent: Thursday, October 14, 2010 11:13 AM
To: Stephen Nadas
Subject: RFC5798

Stephen, I want to ask you a question about this RFC and the VRRP protocol.=
 Regarding section 6.4.3, bullet points (735) to (765).

If 2 vrrp routers became isolated for whatever reason, one router would rem=
ain as master, the other would transition from backup to master and send a =
gratuitous arp (ipv4 only) to notify remote arp caches. My question is abou=
t when the fault is corrected. One router transitions from master to backup=
; the other router still remains as master. The backup router follows (735)=
 to (765), but the master seemingly does nothing at all. In particular the =
now-for-real master does not send a gratuitous arp. This leaves remote arp =
caches with the wrong ip/mac value.

I'm sure this has been considered. What is typically done to prevent this s=
cenario or to recover from it?

Thanks

Carl Petersen


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<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN class=3D882180916-14=
102010>IMO=20
better to ask VRRP list than me, individually, </SPAN></FONT></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN=20
class=3D882180916-14102010>Regards,</SPAN></FONT></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN class=3D882180916-14=
102010>Steve=20
</SPAN></FONT></DIV><BR>
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<HR tabIndex=3D-1>
<FONT face=3DTahoma size=3D2><B>From:</B> Carl Petersen=20
[mailto:[email protected]] <BR><B>Sent:</B> Thursday, October 14, 201=
0=20
11:13 AM<BR><B>To:</B> Stephen Nadas<BR><B>Subject:</B>=20
RFC5798<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV class=3DWordSection1>
<P class=3DMsoNormal>Stephen, I want to ask you a question about this RFC a=
nd the=20
VRRP protocol. Regarding section 6.4.3, bullet points (735) to=20
(765).<o:p></o:p></P>
<P class=3DMsoNormal><o:p>&nbsp;</o:p></P>
<P class=3DMsoNormal>If 2 vrrp routers became isolated for whatever reason,=
 one=20
router would remain as master, the other would transition from backup to ma=
ster=20
and send a gratuitous arp (ipv4 only) to notify remote arp caches. My quest=
ion=20
is about when the fault is corrected. One router transitions from master to=
=20
backup; the other router still remains as master. The backup router follows=
=20
(735) to (765), but the master seemingly does nothing at all. In particular=
 the=20
now-for-real master does not send a gratuitous arp. This leaves remote arp=
=20
caches with the wrong ip/mac value.<o:p></o:p></P>
<P class=3DMsoNormal><o:p>&nbsp;</o:p></P>
<P class=3DMsoNormal>I&#8217;m sure this has been considered. What is typic=
ally done to=20
prevent this scenario or to recover from it?<o:p></o:p></P>
<P class=3DMsoNormal><o:p>&nbsp;</o:p></P>
<P class=3DMsoNormal>Thanks<o:p></o:p></P>
<P class=3DMsoNormal><o:p>&nbsp;</o:p></P>
<P class=3DMsoNormal>Carl Petersen<o:p></o:p></P>
<P class=3DMsoNormal>&nbsp;<o:p></o:p></P></DIV></BODY></HTML>

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