Re: [IPsec] Issue #177

Yoav Nir <ynir@checkpoint.com> Tue, 13 April 2010 11:53 UTC

From: Yoav Nir <ynir@checkpoint.com>
To: Yaron Sheffer <yaronf.ietf@gmail.com>
Date: Tue, 13 Apr 2010 14:52:46 +0300
Thread-Topic: [IPsec] Issue #177
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Cc: "ipsec@ietf.org WG" <ipsec@ietf.org>
Subject: Re: [IPsec] Issue #177
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On Apr 13, 2010, at 1:17 PM, Yaron Sheffer wrote:

> Looks good. A few comments down below.
> 
> 	Yaron
> 
> On Tue, 2010-04-13 at 11:49 +0300, Yoav Nir wrote:
>> 
>>   "Fault Tolerance" is a condition related to high availability, where
>>   a system maintains service availability, even when a specified set of
>>   fault conditions occur.  In clusters, we expect the system to
>>   maintain service availability, when one of the cluster members fails.
> 
> one or more

Agreed. Fixed.

>> 
>>   "Hot Standby Cluster", or "HS Cluster" is a cluster where only one of
>>   the members is active at any one time.  This member is also referred
>>   to as the the "active", whereas the others are referred to as "stand-
>>   bys".  [VRRP] is one method of building such a cluster.
> 
> [Please ignore if you're sick and tired of terminology discussions:] I
> look at the term "hot standby" as contrasted with "warm/cold
> standby" (see http://www.webopedia.com/TERM/H/hot_standby.html). This is
> not what we mean here. Can we use "active-standby" instead?

I can live with that. What do other think?

>>   "Failover" is the event where a one member takes over some load from
>>   some other member.  In a hot standby cluster, this hapens when a
>>   standby memeber becomes active due to a failure of the former active
>>   member, or because of an administrator command.  In a load sharing
>>   cluster this usually happens because of a failure of one of the
>>   members, but certain load-balancing technologies may allow a
>>   particular load (an SA) to move from one member to another to even
>>   out the load, even without any failures.
> 
> The parenthetical "an SA" implies that SAs are never shared between
> members. I suggest that the initial definition of "cluster" mention
> whether we expect IKE and IPsec SAs to be shared between members.

That is not part of terminology. It's mentioned in section 3. How about I change the parenthetical remark to "such as all the flows associated with a particular SA" ?

>>   "Loose Cluster" is a cluster where each member has a different IP
>>   address.  Peers find the correct member using some method such as DNS
>>   queries or [REDIRECT].
> 
> Upon failure, members' IP addresses are reallocated to other members.

They are?