My upstream (data center actually) is migrating to new equipment. They suggested I check the ARP timeout on my switches to ensure minimal downtime, like 1-2 minutes. However, where the two handoffs are ported on 23/24 on the primary switch, the ARP shows 4 hour timeout.
GigabitEthernet1/0/24 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet, address is 002a.107d.8718 (bia 002a.107d.8718)
Description: IO #2
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 28/255, rxload 13/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, media type is 10/100/1000BaseTX
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output never, output hang never
Last clearing of "show interface" counters never
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 6807470
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 54669000 bits/sec, 14369 packets/sec
5 minute output rate 111636000 bits/sec, 21917 packets/sec
5236474889 packets input, 2354768085712 bytes, 0 no buffer
Received 327992 broadcasts (302576 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 302576 multicast, 0 pause input
0 input packets with dribble condition detected
7477085074 packets output, 4137392617238 bytes, 0 underruns
6807470 output errors, 0 collisions, 1 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out
The tech suggested five minutes. From the Cisco docs, I can change it to whatever in config mode using this command
arp timeout seconds
However, is this safe and the proper way to do so, for my migration? I have 24k IPs routed among the primary switch and trunked 2nd switch.
Thanks for your tip in advance.
