Basic arp configuration, Figure 347 p – Brocade 6910 Ethernet Access Switch Configuration Guide (Supporting R2.2.0.0) User Manual
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Brocade 6910 Ethernet Access Switch Configuration Guide
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Address Resolution Protocol
When devices receive this request, they discard it if their address does not match the destination IP
address in the message. However, if it does match, they write their own hardware address into the
destination MAC address field and send the message back to the source hardware address. When
the source device receives a reply, it writes the destination IP address and corresponding MAC
address into its cache, and forwards the IP traffic on to the next hop. As long as this entry has not
timed out, the switch will be able forward traffic directly to the next hop for this destination without
having to broadcast another ARP request.
Also, if the switch receives a request for its own IP address, it will send back a response, and also
cache the MAC of the source device's IP address.
Basic ARP Configuration
Use the IP > ARP (Configure General) page to specify the timeout for ARP cache entries, or to
enable Proxy ARP for specific VLAN interfaces.
CLI References
•
•
Command Usage
Proxy ARP
When a node in the attached subnetwork does not have routing or a default gateway configured,
Proxy ARP can be used to forward ARP requests to a remote subnetwork. When the router receives
an ARP request for a remote network and Proxy ARP is enabled, it determines if it has the best
route to the remote network, and then answers the ARP request by sending its own MAC address to
the requesting node. That node then sends traffic to the router, which in turn uses its own routing
table to forward the traffic to the remote destination.
FIGURE 347
Proxy ARP
Parameters
These parameters are displayed:
•
Timeout – Sets the aging time for dynamic entries in the ARP cache. (Range: 300 - 86400
seconds; Default: 1200 seconds or 20 minutes)
The ARP aging timeout can only be set globally for all VLANs.
The aging time determines how long dynamic entries remain in the cache. If the timeout is too
short, the switch may tie up resources by repeating ARP requests for addresses recently
flushed from the table.
When a ARP entry expires, it is deleted from the cache and an ARP request packet is sent to
re-establish the MAC address.
no routing,
no default
gateway
Remote
ARP Server
Proxy ARP
ARP
request