vlan set up

[aastratech]

hi ,
looking for some guidance, we have inplemented a 100+ ip extns on Evoluition. Using DHCP option 43 the phones get their ip address , VLAN id and correct software. However the customer is using the pc port on the ip phones for his data network. The lan has 2 VLANs 30 for voice and 40 for data, the switch ports sre set to use both VLANs but the pc attached to the phone fails to lease any ip address. config file has entry of;
PhonePort=6,30
PCPort=0,40
LANPort=1,1
any suggestions why this doesnt work...

 

[Mpe]

Just a thought have you set up the switch port to accept 2 diffrent mac adresses on same port at the same time.

 

[aastratech]

Mpe,
I will ask the Network engineers if this is the case. Does the info config file look ok?. Not to sure about priorities on the network.

 

[ADB100]

I think the reason it isn't working is the PC Port is expecting 802.1q Tag's in the packets from the attached PC. Generally the Phone uses Tag's but the PC doesn't:

PhonePort=6,30 ! CoS=6, VLAN=30 IF LANPort=1,x
PCPort=0,1 ! CoS=0, VLAN=1 IF LANPort=x,1
LANPort=1,0 ! PhonePort Tagged, PCPort UnTagged

The switchport the Phone is attached should be configured to Tag the Voice VLAN but have the access VLAN (untagged) VLAN set to 40. If it is a Cisco switch then it should look like this:

interface FastEtherent0/1
switchport
switchport mode access
switchport access vlan 40
switchport voice vlan 30
!

This is then a 'psuedo' trunk allowing the access VLAN and a single Tagged (Voice) VLAN. Alternatively you could hard-code the port as a trunk (you MUST do this on older 2900/3500XL switches):


interface FastEtherent0/1
switchport
switchport mode trunk
switchport trunk native vlan 40
switchport trunk allowed vlan 30
!

HTH

Andy

 

[whosrdaddy]

andy is right, the pc doesn't recognize tagged traffic

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[aastratech]

thanks guys for the quick response. I will modify the config file and pass on other info to network engineers.

 

[ADB100]

If you are using DHCP to supply the VLAN information to the phone through Option 43 then I think the [L2QOS] section of the configuration file is ignored. The ability to supply the Voice VLAN via DHCP option 43 has only been available in recent firmware so check this out. The DHCP option is much better since the phones no longer store the VLAN information in NVRAM so moving them is much simpler. You will know if the DHCP VLAN option is being used as the phones do a soft-boot during startup from cold.

HTH

Andy

 

[aastratech]

Hi ABD100,
Voice VLAN is 30 you would add to the end of your DHCP Option 43:
05 02 33 30
05 being the Tag to indicate that a VLAN ID will follow, 02 indicating the length, then 33 for 03 and 30 for 0

Webserver/software-server is 172.28.136.20 add to Option 43
01 0D 31 37 32 2E 32 38 2E 31 33 36 2E 32 30
01 being the Tag ,
The Option 43 HEX entry would look like:

11 45 72 69 63 73 73 6F 6E 20 49 50 2D 50 68 6F 6E 65 01 0C 31 37 32 2E 32 30 2E 31 36 35 2E 31 05 02 33 30

is this correct to send the VLAN id to the ip-phone. If in the config file L2QOS is ignored how does the PCPORT know which VLAN ID to take?

 

[ADB100]

The PCPort doesn't use VLAN Tags, so packets on the Native/Untagged VLAN leave the switchport without any Tags, enter the Phone and are switched out of the PC Port on the Phone untagged

I believe your option 43 string is incorrect - the length of the Server string is 13 octets not 12 (should be 0D, you list 0C)

11 45 72 69 63 73 73 6F 6E 20 49 50 2D 50 68 6F 6E 65 01 0D 31 37 32 2E 32 30 2E 31 36 35 2E 31 05 02 33 30

You are correct about the VLAN option though (05 02 33 30)

HTH

Andy

 

[aastratech]

Andy,
OD has been entered on tag 05 just a typo on the final string..the phones do pick up the software server..
so just to sum up then, customer has 2 VLANS; VLAN30 for for data voice ip range 172.28.136.xxx and VLAN40 ip range 172.28.137.xxx if we set pcport to untagged will this lease an ip address on 172.28.137.xxx with VLAN id 40 ?

 

[ADB100]

As far as the PC is concerned it isn't on a VLAN - it will send and receive packets without VLAN Tags. It is the switch that dictates the Access VLAN. As I listed previously a Cisco switch configured to allow access from an IP Phone with a 'piggy-backed' PC should look like:

interface FastEtherent0/1
switchport
switchport mode access
switchport access vlan 40
switchport voice vlan 30
!

This allows the IP Phone to send & receive packets with 802.1q Tags of VLAN 30 (as long as the Phone learns the VLAN Tag through DHCP or the Config File), and the PC to send & receive packets without VLAN Tags. The packets from the Phone will be handled by VLAN 30 on the switch and packets from the PC will be handled by VLAN 40 on the switch.

HTH

Andy

 

[aastratech]

cheers Andy,

understand now, thanks for you help