Re: LAN failover
- From: "greco" <grecot@xxxxxxxxx>
- Date: 21 Oct 2006 10:21:48 -0700
Volker,
you're are right to the ARP enviroment, but in this case, is there any
detailed documentation besides System's Manager Vol 2, detailing LAN
Failover in OpenVMS?
I'm plugged into two Cisco different switches, it might me related to
arp-cache in the Cisco switches as well, right?
In case of failover does LAN failover shouldn't send arp-whois
broadcast to switches so new ARP address be automatically updated?
Cheers,
Volker Halle wrote:
Here is a theory on what may be happening:
Your DS25 LAN interfaces are probably connected to LAN switches, maybe
even to different ones. The switch(es) need(s) to learn, that the MAC
address of the LAN failover device is now active on a different switch
port.
The first ethernet packet being sent from the DS25 via the new LAN
device (after the failover) should teach the switch which port this MAC
address is on now.
If PING is using the MAC address from the local ARP cache on the remote
node and is sending the ICMP packet directly to the DS25 LLA0 MAC
address, the switch will probably forward the packet to the - now
inactive - LAN device on your DS25.
If PING would not be using the ARP cache entry (try an arp -d ds25
before the PING ds25), it would send an ARP who-is broadcast, which
should also be delivered to the new LAN device and it should reply,
teaching the switch the new port for this MAC address.
Volker.
.
- References:
- LAN failover
- From: grecot
- Re: LAN failover
- From: Volker Halle
- LAN failover
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