Understanding ARP cache

Is my understanding correct?

ARP is a table of devices which are currently connected on the network.

So when a new network is setup the router or managed switch stores the ip addresses and MAC addresses in a table. The table is created when a single device sends out an ARP request (i.e. broadcast) to check if a device is on the network using a MAC address.

thats the first thing.

second thing is if we flush the ARP - does that mean we reset the ARP cache which would result in the devices losing connectivity temporarily?

please advise in both scenarios.
Ikky786Asked:
Who is Participating?
 
Dave BaldwinConnect With a Mentor Fixer of ProblemsCommented:
No, ARP is Address Resolution Protocol, a method to turn IP addresses basically into MAC addresses on the LAN.  When an address is converted, a copy of the info is stored in the ARP cache.  When you clear the cache, it just means that the process has to be repeated instead of the information coming from the cache.  ARP is strictly for LAN access.  

http://en.wikipedia.org/wiki/Address_Resolution_Protocol#Example
0
 
OomWallCommented:
It might be easier if you let us know what you are trying to troubleshoot.
0
 
jmathonCommented:
I already did an arp cache flush on a switch without any connectivity loss.
Since the flush is done, you will have new arp requests
0
 
skullnobrainsConnect With a Mentor Commented:
ARP is a table of devices which are currently connected on the network.
no arp is a protocol. hosts only maintain a cache containing the IPs and mac addresses of the devices they already communicated with

So when a new network is setup the router or managed switch stores the ip addresses and MAC addresses in a table. The table is created when a single device sends out an ARP request (i.e. broadcast) to check if a device is on the network using a MAC address.

not really
ARP requests are not sent to a MAC adress. they are intended to retrieve the mac address corresponding to an IP.

also note that although ARP works in shoutcast mode, using the term broadcast is confusing.

second thing is if we flush the ARP - does that mean we reset the ARP cache which would result in the devices losing connectivity temporarily?

no. the ARP protocol will be used for the next packet that is sent and the cache will be repopulated as needed. on a busy network, it will be back to the previous state before you have a chance to see it empty
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.