Subject: RE: [VRRP] draft-ietf-vrrp-unified-mib-06 - AdvInterval

From: "Fioramonti, Joseph" <[email-masked]>
Date: Thu, 22 Mar 2007 15:20:25 -0400

Kalyan,

You can't change the units to seconds, because VRRPv3 uses centiseconds.

Lets say that in a set operation on a VRRPv2 VR, 50 (centiseconds) is
provided for vrrpOperAdvertisementInterval.  What shall we do with it?

Thanks,

--Joe.

  _____  

From: [email-masked] [mailto:[email-masked]] 
Sent: Thursday, March 22, 2007 3:05 PM
To: [email-masked]; [email-masked]
Subject: RE: [VRRP] draft-ietf-vrrp-unified-mib-06 - AdvInterval

Hi Joe,

The change was originally made to accommodate sub second timers that was
proposed in 

 Timer Enhancements to Reduce Failover Times for the
              Virtual Router Redundancy Protocol for IPv4
 
                  <draft-ietf-vrrp-ipv4-timers-02.txt
<http://tools.ietf.org/html/draft-ietf-vrrp-ipv4-timers-02.txt> >
It was a mistake to reference to RFC 3768 for this in the unified-MIB.

Now that the draft has expired, I can either change the units back to
seconds or leave it as cent seconds if some one is going to 

update the draft. 

When the device is managed by vrrpOperationsTable rather than by
vrrpOperTable the advertisement interval is given in centiseconds.  However
in RFC 3768 the advertisement interval is in seconds.  What is the intention
with respect to the conversion of centiseconds to seconds for RFC 3768 and
IPv4?

I did not understand what the problem is. If a router implements 3768 and
unified MIB, the vrrpOperAdvertisementInterval 

will return 100/200/300/etc.  in centiseconds instead of 1/2/3/etc. seconds.

Thanks, 
Kalyan 

  _____  

From: ext Fioramonti, Joseph [mailto:[email-masked]] 
Sent: Thursday, March 22, 2007 7:27 AM
To: [email-masked]'
Subject: [VRRP] draft-ietf-vrrp-unified-mib-06 - AdvInterval

Folks,

I have a question about the units intended for the AdvInterval.

In RFC 2787 we have seconds:

 vrrpOperAdvertisementInterval OBJECT-TYPE

     SYNTAX       Integer32 (1..255)

     UNITS        "seconds"

     MAX-ACCESS   read-create

     STATUS       current

     DESCRIPTION

         "The time interval, in seconds, between sending

         advertisement messages. Only the master router sends

         VRRP advertisements."

     DEFVAL       { 1 }

     ::= { vrrpOperEntry 11 }

The above is deprecated by draft-ietf-vrrp-unified-mib-06, which has
centiseconds:

       vrrpOperationsAdvInterval OBJECT-TYPE  

           SYNTAX       TimeInterval (1..4096)  

           UNITS        "centiseconds"  

           MAX-ACCESS   read-create  

           STATUS       current  

           DESCRIPTION  

               "The time interval, in centiseconds, between sending  

               advertisement messages. Only the master router sends  

               VRRP advertisements."  

           REFERENCE " RFC 3768 section 5.3.7" 

           DEFVAL       { 100}  

           ::= { vrrpOperationsEntry 9 }  

It references RFC 3768 section 5.3.7 which has seconds:

   The Advertisement interval indicates the time interval (in seconds)

   between ADVERTISEMENTS.  The default is 1 second.  This field is used

   for troubleshooting misconfigured routers.

When the device is managed by vrrpOperationsTable rather than by
vrrpOperTable the advertisement interval is given in centiseconds.  However
in RFC 3768 the advertisement interval is in seconds.  What is the intention
with respect to the conversion of centiseconds to seconds for RFC 3768 and
IPv4?  Here are my three favorite alternatives:

1.  Round (or truncate) centiseconds to seconds.  Run a seconds-based
advertisement timer.  (if we round/truncate what do we report in a get?)

2.  Actually run a centiseconds-based advertisement timer, but the
advertisement interval carried in ADVERTISEMENTS is rounded up to the next
higher second.  (this would be a nice way to get sub-second failover for
IPv4)

3.  Reject values of centiseconds not evenly divisible by 100.

Thanks,

--Joe.

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---

From: <[email-masked]>
Date: Thu, 22 Mar 2007 15:24:43 -0500

hi Joe,

Thats true, sorry about that. 

Now I see the problem :). I liked steve's suggestion :

Do we need the "units" clause at all or can we provide an "or" condition
like we do with the alaVrrp3AssoIpAddr inetAddress?  If we do any type
of rounding we won't be able to reach the VRRPv2 maximum of 255 seconds.
The interpretation of the field and it's maximum value could be
determined based on the version.  If words to that effect in the
description were sufficient that would be my vote.

Thanks

Kalyan

________________________________

Hi Joe,

 

update the draft. 

When the device is managed by vrrpOperationsTable rather than by
vrrpOperTable the advertisement interval is given in centiseconds.
However in RFC 3768 the advertisement interval is in seconds.  What is
the intention with respect to the conversion of centiseconds to seconds
for RFC 3768 and IPv4?

I did not understand what the problem is. If a router implements 3768
and unified MIB, the vrrpOperAdvertisementInterval 

will return 100/200/300/etc.  in centiseconds instead of 1/2/3/etc.
seconds.

Thanks, 
Kalyan 

________________________________

Folks,

     UNITS        "seconds"

     MAX-ACCESS   read-create

     STATUS       current

     DESCRIPTION

         VRRP advertisements."

     DEFVAL       { 1 }

     ::= { vrrpOperEntry 11 }

           UNITS        "centiseconds"  

           MAX-ACCESS   read-create  

           STATUS       current  

           DESCRIPTION  

               VRRP advertisements."  

           DEFVAL       { 100}  

When the device is managed by vrrpOperationsTable rather than by
vrrpOperTable the advertisement interval is given in centiseconds.
However in RFC 3768 the advertisement interval is in seconds.  What is
the intention with respect to the conversion of centiseconds to seconds
for RFC 3768 and IPv4?  Here are my three favorite alternatives:

2.  Actually run a centiseconds-based advertisement timer, but the
advertisement interval carried in ADVERTISEMENTS is rounded up to the
next higher second.  (this would be a nice way to get sub-second
failover for IPv4)

Thanks,

--Joe.