arp traffic

Answered Question
Aug 8th, 2007
User Badges:

Is there anyway to prevent so much arp traffic? I am seeing that we are having a ton of it and would like to set something up so the computers dont have to broadcast all the time.

Correct Answer by Jon Marshall about 9 years 11 months ago

Hi Matthew


Yes, you can statically map all the mac-addresses on your switches/routers/clients/servers if you really want to remove the broadcasts.

But this is not really practical. Arp is a normal part of the TCP/IP and the broadcasts should not propogate beyond the local vlan.


What you could do is increase the arp timers on all your devices so an arp entry remains in the arp cache for longer.


HTH


Jon

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 5 (1 ratings)
Loading.
Correct Answer
Jon Marshall Wed, 08/08/2007 - 07:38
User Badges:
  • Super Blue, 32500 points or more
  • Hall of Fame,

    Founding Member

  • Cisco Designated VIP,

    2017 LAN, WAN

Hi Matthew


Yes, you can statically map all the mac-addresses on your switches/routers/clients/servers if you really want to remove the broadcasts.

But this is not really practical. Arp is a normal part of the TCP/IP and the broadcasts should not propogate beyond the local vlan.


What you could do is increase the arp timers on all your devices so an arp entry remains in the arp cache for longer.


HTH


Jon

MZydorczyk2 Wed, 08/08/2007 - 07:41
User Badges:

I didnt think it would be practical but thanks for that suggestion, i will try it. Thanks.

Jon Marshall Wed, 08/08/2007 - 07:45
User Badges:
  • Super Blue, 32500 points or more
  • Hall of Fame,

    Founding Member

  • Cisco Designated VIP,

    2017 LAN, WAN

Matthew


You can do this but beware that if you increase the arp cache that means you have to wait longer for it to time ou eg.


you have a user PC that is broken. You change the PC and give it the same IP address. For it to work you will have to wait until the arp caches time out the entry.


Generally speaking arp cache timers have been decided by vendors after years of experience with ethernet so please be careful when changing.


Jon

wochanda Wed, 08/08/2007 - 15:12
User Badges:
  • Silver, 250 points or more

interface vlan 100

arp timeout 300

Actions

This Discussion