11-01-2007 08:32 PM - edited 03-03-2019 05:38 AM
I am trying to duplicate a VLAN setup that I have used successfully on 1700 routers on a 871 router. I purchased the Adv IP Services version of the 871 (no wireless) which is supposed to be able to do 4 dot1q VLANs. However I am realizing since the Fa0-3 interfaces on this little guy are not L3 interfaces I can't use my tried and true setup. I can't find much on how to do this other than the fact that it seems I am going to have to use bridging and BVI interfaces. What are BVI interfaces? Can they help me create something like I am showing below? If so, can anybody point me to some examples?
Thanks,
Diego
interface FastEthernet0
ip address 10.1.1.1 255.255.255.0
!
interface FastEthernet0.2
encapsulation dot1Q 2
ip address 10.1.2.1 255.255.255.0
!
interface FastEthernet0.3
encapsulation dot1Q 3
ip address 10.1.3.1 255.255.255.0
!
Solved! Go to Solution.
11-05-2007 03:05 PM
By default, switchports are set for dynamic trunking.
If you connect a workstation, it will negotiate to access mode.
If you connect another switch with the same characteristics, the switchport will trunk.
As I stated before, if you connect a workstation to a switchport and the mode is to set to an access vlan #,
it will send a dhcp-request packet on that Vlan.
A DHCP server listening on that Vlan will reply with an IP address, if available.
If the DHCP server resides in another Vlan, you need to configure ip helper-address on the Layer3 gateway from that Vlan pointing to the remote DHCP server.
The DHCP server scope will need to have the default gateway information under the scope and this needs to match from the Layer3 gateway above.
As for the switchport mode query, this document provides some information:
11-01-2007 09:14 PM
The VLAN support is configured using the Cisco IOS switching commands.
Layer 3 interfaces example
interface vlan 1
description LAN1
ip add 192.168.1.1 255.255.255.0
!
interface vlan 2
description LAN2
ip add 192.168.2.1 255.255.255.0
!
interface vlan 3
description LAN3
ip add 192.168.3.1 255.255.255.0
!
interface vlan 4
description LAN4
ip add 192.168.4.1 255.255.255.0
!
Than you have the switch interfaces that you can set up as a trunk or individually associated to a VLAN as an access port.
As a trunk
interface fa0
description switch1
switchport mode trunk
As an access port
interface fa0
description switch1
switchport mode access
switchport access vlan 2
Daniel
11-02-2007 06:52 AM
Well the router accepts those command without complaining but when I do a "show vlans" I get "No Vlans configured". Seems like I need to do a bit more. Any ideas?
Thanks,
Diego
11-02-2007 07:32 AM
That command only works on real switches, try sh vlan-switch on these hybrid devices :)
11-02-2007 07:55 AM
The sho vlan-switch also shows no VLANs. This is the output from that command:
Router#sho vlan-swit
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0, Fa1, Fa2, Fa3
1002 fddi-default active
1003 token-ring-default active
1004 fddinet-default active
1005 trnet-default active
VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
1 enet 100001 1500 - - - - - 1002 1003
1002 fddi 101002 1500 - - - - - 1 1003
1003 tr 101003 1500 1005 0 - - srb 1 1002
1004 fdnet 101004 1500 - - 1 ibm - 0 0
1005 trnet 101005 1500 - - 1 ibm - 0 0
Router#
11-02-2007 07:59 AM
It's not showing because you haven't create them. The previous poster guided you on configuring Layer3 SVIs but you also need to configure Layer2 Vlans on the VTP database.
The steps are:
router#vlan management
vlan 2
vlan 3
vlan 4
exit
11-02-2007 08:07 AM
I never could get my 871, nor can I get my 1811, to show VLANs with the "sh vlans" command. However, if you hook up a catalyst switch, set it up correct with a trunk, it'll broadcast the VLANs properly.
*shrug* If you go into the vlan database, though, they're there. *shrug*
edit: Whoooooooops. . .nevermind. Missed a few key posts in the thread.
11-02-2007 09:38 AM
You don't need to create the vlans in the database.
They will function without doing that.
Daniel
11-02-2007 11:06 AM
That command is not available on my router. The only vlan command avail is "vlan accounting". It is interesting that one poster's advice is to simply ignore the fact that they don't show. I will try some tests even though I am not sure the VLANs are there yet.
Diego
11-02-2007 11:21 AM
If you created the interfaces for them (ie, int vlan x), then they've been created. You just have to make sure they're not shut down.
You can also look in the actual vlan database. In global config (provided it still exists), type vlan database.
11-02-2007 11:55 AM
Don't go into config mode.
Vlan Database is not a config command but an exec command.
_______________
Rack1SW1#vlan data
Rack1SW1(vlan)#vlan 2
VLAN 2 added:
Name: VLAN0002
Rack1SW1(vlan)#vlan 3
VLAN 3 added:
Name: VLAN0003
Rack1SW1(vlan)#vlan 4
VLAN 4 added:
Name: VLAN0004
Rack1SW1(vlan)#exit
APPLY completed.
Rack1SW1#sh vlan-switch
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa1/0, Fa1/1, Fa1/2, Fa1/3
Fa1/4, Fa1/5, Fa1/6, Fa1/7
Fa1/8, Fa1/9, Fa1/10, Fa1/11
Fa1/12, Fa1/13, Fa1/14, Fa1/15
2 VLAN0002 active
3 VLAN0003 active
4 VLAN0004 active
________________________________
Can you post the show ip interface bri | ex una output before and after the commands above ?
11-02-2007 12:29 PM
Looks like we are making progress now. I have attached a file with the output you requested. What if I now need to add two devices to each port. One PC and one IP phone. The PCs do not support dot1q and the phones can be configured for VLAN ID2. I believe that I need to make all switchports trunk ports no? Also, if I have two DHCP pools how do I assign one pool to VLAN1 and the second pool to VLAN2?
Thanks,
Diego
11-02-2007 02:13 PM
I don't see any attached file.
So the PCs will connect via the phone ?
If so, configure the phones for one Vlan and the workstation for another vlan.
_______________
interface FastEthernet x/x
switchport access vlan 3
switchport voice vlan 2
___________________
11-03-2007 04:43 PM
I have two questions for the above:
1) Will PCs work on VLAN 3 if they don't support or have any type of VLAN capability? I thought it would be easiest to simply have them use the native VLAN 1
2) I have setup two DHCP pools. How do I assign the pools to the correct VLANs?
Thanks,
Diego
11-03-2007 07:34 PM
1) PCs won't know what Vlan they belong to. It's up to the switch to place those devices in the correct Vlan. If you assign Vlan 3 as the access vlan, that's what the PCs will use.
2) What type of DHCP server are you using ? Under the pool, you will want a default router -or- gateway. This value will determine the correct scope when assigning dynamic addresses.
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