From: Jonathan V Hays (jhays@jtan.com)
Date: Fri Jul 25 2003 - 22:29:22 GMT-3
Deepesh,
Ah, I believe I understand what you are thinking.
But although extended vlan 1026 was created by the software on your
switch when you created routed port fa0/11, that does *not* mean that
vlan 1026 is a switched virtual interface. A routed port forces the
creation of a vlan for internal software usage, but it does not make
that vlan into an SVI.
For example, here I configure both an SVI (vlan 2 is 192.168.1.1) and a
routed port (fa0/1 is 172.16.1.1). Note that the SVI vlan has been
configured as an access vlan on port fa0/2.
############
Switch#sh run
!
[output omitted]
!
interface FastEthernet0/1
no switchport
ip address 172.16.1.1 255.255.255.0
!
interface FastEthernet0/2
switchport access vlan 2
switchport mode access
no ip address
!
interface FastEthernet0/3
no ip address
!
[output omitted]
!
interface Vlan2
ip address 192.168.1.1 255.255.255.0
On my switch, extended vlan 1027 was created by the switch IOS.
############
Switch#sh vlan internal usage
VLAN Usage
---- --------------------
1027 FastEthernet0/1
Switch#
But when I display a list of SVI's using the "show interfaces vlan"
command, the switch indicates that vlan 1027 is not an SVI:
############
Switch#show interfaces vlan 2
Vlan2 is up, line protocol is up
Hardware is EtherSVI, address is 000c.8581.6380 (bia 000c.8581.6380)
Internet address is 192.168.1.1/24
MTU 1500 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 00:06:13, 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: 2
Queueing strategy: fifo
Output queue :0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute ouxtput rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts, 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
Switch#show interfaces vlan 1027
^
% Invalid input detected at '^' marker.
Switch#
Also, the "sh int status" output indicates that 1027 does not below to
any useful vlan, as far as switching or routing is concerned.
############
Switch#sh int status
Port Name Status Vlan Duplex Speed Type
Fa0/1 notconnect routed auto auto
10/100BaseTX
Fa0/2 notconnect 2 auto auto
10/100BaseTX
[output omitted]
The "sh ip int brief" command gives a list of IP addresses associated
with SVIs and routed ports, and you can see that internal vlan 1027 is
not included as an SVI.
############
Switch#
Switch#sh ip int brief
Interface IP-Address OK? Method Status
Protocol
Vlan1 unassigned YES unset administratively
down down
Vlan2 192.168.1.1 YES manual up
up
FastEthernet0/1 172.16.1.1 YES manual down
down
FastEthernet0/2 unassigned YES unset down
down
Fa
As a last test, I should be able to assign an SVI vlan to one or more
layer 2 ports, as I did when I assigned SVI vlan 2 to interface fa0/2
above. Let's see what happens if I try it on the unused port fa0/3.
############
Switch(config)#int fa0/3
Switch(config-if)#switchport mode access
Switch(config-if)#switchport access vlan 1027
% Access VLAN does not exist. Creating vlan 1027
Switch(config-if)#
00:29:01: %PM-4-EXT_VLAN_INUSE: VLAN 1027 currently in use by
FastEthernet0/1
00:29:01: %PM-2-VLAN_ADD: Failed to add VLAN 1027 - VTP error.
Switch(config-if)#
You have brought up a very interesting point. Thanks!
Jonathan
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Deepesh Chouhan
Sent: Friday, July 25, 2003 8:50 PM
To: Jonathan V Hays; ccielab@groupstudy.com
Subject: RE: Routed ports on the 3550
No
Routed-port = SVI port of avaliable extended VLAN (1006-4096)
switch-2#sh run inter f0/11
Building configuration...
Current configuration : 64 bytes
!
interface FastEthernet0/11
no switchport
no ip address
end
switch-2#sh vlan internal usage
VLAN Usage
---- --------------------
1026 FastEthernet0/11
switch-2#
in this case
routed-port f0/11 = SVI of 1026
f0/11 = switchport of 1026
So f0/11 is associated with VLAN 1026, but is also SVI of itself
thanks
deepesh
> -----Original Message-----
> From: Jonathan V Hays [mailto:jhays@jtan.com]
> Sent: Friday, July 25, 2003 5:37 PM
> To: 'Deepesh Chouhan'; ccielab@groupstudy.com
> Subject: RE: Routed ports on the 3550
>
>
> I think you mean that a routed-port does *not* have a VLAN number
> associated with it, correct?
>
>
http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/12113ea1/3550s
> cg/swint.htm#1035057
>
> quote:
>
> A routed port is a physical port that acts like a port on a router; it
> does not have to be connected to a router. A routed port is not
> associated with a particular VLAN, as is an access port. A routed port
> behaves like a regular router interface, except that it does not
support
> VLAN subinterfaces. Routed ports can be configured with a Layer 3
> routing protocol.
>
> end quote.
>
> Yes. I have seen little use for the routed port, other than playing
> around with scenarios for the lab test. The SVI seems much more useful
> and flexible.
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