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Community Member

about svi mtu

hello netpro:

i increate a int vlan x in sw3550emi ,I have no configure,but the int vlan x show it's mtu 1501.who can tell me what's the problem? thank you

sw1#sh int vlan 5

Vlan5 is up, line protocol is up

Hardware is EtherSVI, address is 0013.1ab4.fe00 (bia 0013.1ab4.fe00)

MTU 1501 bytes, BW 1000000 Kbit, DLY 10 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

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: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

0 packets input, 0 bytes, 0 no buffer

Received 0 broadcasts (0 IP multicast)

0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 packets output, 0 bytes, 0 underruns

0 output errors, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

sw1#sh run int vlan 5

interface Vlan5

no ip address


sh version

IOS (tm) C3550 Software (C3550-I5Q3L2-M), Version 12.1(20)EA1, RELEASE SOFTWARE


Copyright (c) 1986-2004 by cisco Systems, Inc.

Compiled Wed 04-Feb-04 23:28 by yenanh

Image text-base: 0x00003000, data-base: 0x00827298

ROM: Bootstrap program is C3550 boot loader

sw1 uptime is 5 minutes

System returned to ROM by power-on

System image file is "flash:/c3550-i5q3l2-mz.121-20.EA1.bin"

cisco WS-C3550-24 (PowerPC) processor (revision P0) with 65526K/8192K bytes of m


Processor board ID CAT0819X0FZ

Last reset from warm-reset

Bridging software.

Running Layer2/3 Switching Image

Community Member

Re: about svi mtu

I'm not sure if there is a problem becuase a standard Ethernet frame MTU is 1500 bytes. This does not include the Ethernet header and Cyclic Redundancy Check (CRC) trailer, which is 18 bytes in length, to make the total Ethernet frame size of 1518.

Community Member

Re: about svi mtu

thank u for your attention.

I can't understand that the default mtu is 1500 but why there is 1501 .

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