DHCP issue on 1811w does not provide IP to connected Laptop

[mahesh18]

Hi Everyone,

I am setting up 1811w router for accessing internet.

DHCP is configured on it but it is not providing IP to laptop connected on port fa6.

Here is config of router

dot11 ssid internet

vlan 98

authentication open

authentication key-management wpa

guest-mode

wpa-psk ascii 0 010907150A59111C390C

!

ip source-route

!

!

!

ip dhcp pool WIRELESS

   import all

   network 192.168.98.0 255.255.255.0

   default-router 192.168.98.1

   dns-server 4.2.2.2

   lease 3

!

!

ip cef

no ipv6 cef

!

multilink bundle-name authenticated

!

!

!

vtp mode transparent

!

!

!

archive

log config

  hidekeys

!

!

vlan 98

!

bridge irb

!

!

!

interface Dot11Radio0

no ip address

!

encryption vlan 98 mode ciphers tkip

!

ssid internet

!

speed basic-1.0 basic-2.0 basic-5.5 6.0 9.0 basic-11.0 12.0 18.0 24.0 36.0 48.0

54.0

station-role root

no cdp enable

!

interface Dot11Radio0.1

!

interface Dot11Radio0.98

encapsulation dot1Q 98

no cdp enable

bridge-group 98

bridge-group 98 subscriber-loop-control

bridge-group 98 spanning-disabled

bridge-group 98 block-unknown-source

no bridge-group 98 source-learning

no bridge-group 98 unicast-flooding

!

interface Dot11Radio1

no ip address

shutdown

speed basic-6.0 9.0 basic-12.0 18.0 basic-24.0 36.0 48.0 54.0

station-role root

!

interface FastEthernet0

ip address dhcp

ip nat outside

ip virtual-reassembly

duplex auto

speed auto

!

interface FastEthernet1

no ip address

shutdown

duplex auto

speed auto

!

interface FastEthernet2

!

interface FastEthernet3

!

interface FastEthernet4

!

interface FastEthernet5

!

interface FastEthernet6

switchport access vlan 98

!

interface FastEthernet7

!

interface FastEthernet8

!

interface FastEthernet9

!

interface Vlan1

no ip address

shutdown

!

interface Vlan98

no ip address

!

interface Async1

no ip address

encapsulation slip

!

interface BVI98

ip address 192.168.98.1 255.255.255.0

ip nat inside

ip virtual-reassembly

ip tcp adjust-mss 1452

!

ip forward-protocol nd

no ip http server

no ip http secure-server

!

!

!

!

!

!

!

!

!

control-plane

!

bridge 98 protocol ieee

bridge 98 route ip

!

line con 0

line 1

modem InOut

stopbits 1

speed 115200

flowcontrol hardware

line aux 0

line vty 0 4

login

!

end

thanks

mahesh

[mahesh18]

Hi Rick,

I will try that in evening

And will let you know.

Thanks

Mahesh

[mahesh18]

Hi Rick,

I did as you said

interface Vlan98

no ip address

bridge-group 98

!

After doing this

sh int brief

Vlan98                     unassigned      YES NVRAM  up                    down

1811w#

As you see vlan 98 went to up down status

Thanks

MAhesh

[Richard Burts]

Mahesh

I am surprised at this. Please post the output of show interface status

Did anything in the config change other than adding the bridge-group to vlan 98?

HTH

Rick

[mahesh18]

Hi Rick,

nothing changed .

here is info as per you

1811w#sh int status

Port    Name               Status       Vlan       Duplex Speed Type

Fa2                        notconnect   1            auto    auto 10/100BaseTX

Fa3                        notconnect   1            auto    auto 10/100BaseTX

Fa4                        notconnect   1            auto    auto 10/100BaseTX

Fa5                        notconnect   1            auto    auto 10/100BaseTX

Fa6                        connected    98         a-full   a-100 10/100BaseTX

Fa7                        notconnect   1            auto    auto 10/100BaseTX

Fa8                        notconnect   1            auto    auto 10/100BaseTX

Fa9                        notconnect   1            auto    auto 10/100BaseTX

Thanks

Mahesh

[Richard Burts · Accepted solution]

Mahesh

Please try this in addition to my previous suggestion.
Interface VLAN 98
Bridge-group 98 spanning-disabled

HTH

Rick

Sent from Cisco Technical Support iPad App

[mahesh18]

Hi Rick,

This did the magic.

After adding bridge-group 98 spanning-disabled under  int vlan 98.

Desktop PC got IP from DHCP pool of Wi fi.

Thanks for help on the issue all the way.

Need to ask you what does the command

Bridge-group 98 spanning-disabled   did?

Best regards

MAhesh

[Richard Burts · Accepted solution]

Mahesh

This command disables spanning tree from running on the interface. Here is a link to a command reference which explains a bit more about it.

http://www.cisco.com/en/US/docs/ios/bridging/command/reference/br_a1.html#wp1015030

The logic that I used was this:

- the wired ports are in a vlan.

- for PCs connected to ports in the wired vlan to get addresses from DHCP there must be an IP address on the vlan or the vlan must be related to IRB and the BVI.

- you demonstrated that putting an IP address on the vlan will allow DHCP to work. But it requires that there be a separate DHCP pool. And you wanted to use the same pool for wired and wireless.

- So the wired vlan needed to relate to IRB and the BVI.

- the way to relate the vlan to IRB and the BVI is with the bridge-group command.

- But when you applied the bridge-group 98 command to the vlan then the vlan went to protocol down.,

- So I assumed that there should be some other command related to bridge-group that would allow the vlan to stay up. So I looked for other bridge-group commands.

HTH

Rick

[mahesh18]

Hi Rick,

Many thanks for all the help in last few days on this issue.

Its always pleasure to read your answers in the forum.

Best regards

MAhesh