|
Having the same MACs on 2 different NICs in normal
circumstances (ON THE SAME LAN SEGMENT) is a big no no. In high
availability situations though, it is desirable. This way, after a failure
in the primary device, the secondary can assume immediate duties as the primary
and other machines will not have to ARP out for the new MAC address --
which can take quite some time. The trick is that ONLY ONE device will
answer for the MAC at any given time under normal operating circumstances.
It does not matter if the duplicate MAC is virtual (as in VRRP or HSRP for you
Cisco fans) or real as in some proprietary systems.
As far as the SUN machine and some routers (for
instance the SSR/XP product line from Enterasys) which have the same MAC for all
ports on the device in question; this is normally not a problem since you
usually do not have multiple NICs in the same LAN segement answering for
multiple IP addresses -- and anyway -- both aforementioned devices have
mechanisms to override the defaults and have multiple MACs when
necessary.
Regards
----- Original Message -----
Sent: Thursday, August 08, 2002 4:55
PM
Subject: Re: [FW-1] High Availability
with different MAC's
Either way having the same MAC address on 2
seperate NICS plugged within the same network will hose it.
----- Original Message -----
Sent: Thursday, August 08, 2002 12:38
PM
Subject: Re: [FW-1] High Availability
with different MAC's
That's not entirely true. Some companies, SUN for one, have a
MAC unique to the machine, not the card. You can override this with a
firmware command (if needed I'll dredge it up).
Dan Guinn
NetStar Communications
How come you have the same MAC address? It's
usually unique to the card, and there are no two NICs in the world that
have the same MAC. Correct me if I'm wrong. Are you talking about network
cards?
**********************************
Roman
Zeltser,
@National
Computer Center,
DNE
RS Information
Systems
Hi all.
Is posible to configure HA with diferent
MAC's?
We´re using HA with the same MAC and IP
address, but we're having problems with our switches, some of our
established sessions cut or have delays to connect.
thanks in advanced.
---
Incoming mail is certified Virus Free.
Checked
by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.381 /
Virus Database: 214 - Release Date:
8/2/2002
---
Outgoing mail is certified Virus Free.
Checked
by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.381 /
Virus Database: 214 - Release Date:
8/2/2002
|
