Inter-VLAN Multicast IP Routing using a 3560X Switch

[Jeff Harned]

Hello All,

I have a 3560x switch upgraded with the "ip services" license required to do IP multicast routing.  I could use some help with

this since I am having a difficult time on getting things to work correctly. 

I have attached two files; one of the block diagram and one with the configuration of the switch.  I am taking four separte serial input

data streams and converting them each to four separte multicast IP adresses: 239..1.1.3 thru 239.1.1.6.  These four are sent over a single

cable to the switch which I hoped I would be able to route the multicast data to two IP to Serial data conversion units.

These units have LEDs to show data activity but these will just not fire!

Please any help and commnents.

Thanks.

Regards,

Jeff

[Jon Marshall]

Jeff

2) The IP to serial convertors must have an IP address though eg. when they make an IGMP request or send a response they must use an IP to do this.

Do you know what they are.

3) Can you possible SPAN the port connected to the vlan IP to serial convertor to see if the multicast stream is actually being sent to it ?

Jon

[Jeff Harned]

Jon

Maybe this is the problem but I will have to do some further research on this.  I know the Converter units are not receiving any multicast data because all these unit have LEDs indicating receive or transmit activity and they are all out!!!  Wireshark

also confirms there is no multicast data.

I will have to research this and perhaps talk to someone who knows these converter units better than myself.  I will try

to post you tomorrow.

Thanks.

Regards,

Jeff

[Jon Marshall]

Jeff

What are the IP subnets being used for vlan 5 and vlan 10 ?

Jon

[Jon Marshall]

Jeff

I'm a bit confused by your outputs. From the switch config -

interface Vlan1

ip address 172.26.70.52 255.255.255.0

!

interface Vlan5

ip address 10.1.2.2 255.255.255.0

ip pim dense-mode

!

interface Vlan10

ip address 10.1.3.2 255.255.255.0

ip pim dense-mode

!

interface Vlan15

ip address 10.1.10.2 255.255.255.0

ip pim dense-mode

but from the "sh ip igmp groups"  -

cisco4#show ip igmp groups

IGMP Connected Group Membership

Group Address   Interface               Uptime   Expires   Last Reporter   Group Accounted

239.1.1.3       Vlan10                   02:10:58 00:02:40 172.26.7.30

239.1.1.2       Vlan5                   02:13:16 00:02:42 172.26.71.53

239.1.1.5       Vlan15                   02:09:32 00:02:42 172.26.71.28

239.1.1.4       Vlan10                   02:10:56 00:02:43 172.26.71.30

224.0.1.40       Vlan15                  00:12:16 00:02:45 10.1.10.2

all the reporters are using 172.26.x addressing but these are not the addresses being used for the vlan IP subnets according to your switch config ?

Jon

[Jeff Harned]

Jon

I am confused!!  The switch config I sent is correct.

The 172.26.71.30 address I am using to be able to talk to the  IP to Serial converter unit so I can configure it to receive

multicast addresses (data).  This unit is attached to port 1 of the switch.

The 172.26.71.28 address is used  for the second unit which is attached to port 2 of the switch.

The 172.26.71.53 is the address of one of the Serial to IP converter modules.  This is the the Eth port used to send one of the

the converted data with an multicast address of 239.1.1.3.

I do not know what 239.1.1.2 is; I am not using this adddress for any of the conversion processes.  What is 224.0.1.40?

Thanks.

Regards,

Jeff

[Jon Marshall]

Jeff

So from the switch can you ping 172.26.71.x addresses ?

If you can i'm not sure how this is working because none of your L3 vlan interfaces on the 3560 have a 172.26.71.x address.

I would expect the units to have IPs from the same IP subnets as the L3 vlan interfaces on the 3560.

Jon

[Jeff Harned]

Hi Jon

New day.

The only one I can ping is the xxx.xx.71.30

I appaerntly have a misunderstading on how to set up ports to pass multicast data.  I am uncertaian on how regular IP addressess interact

with the multicast addresess.

Ok, what I have done is to make another drawing that includes the ip addresses used .  As use can see the xxx.xx.70.xx ones are

used to access all the switches and converter units for configuration and management.  The xxx.xx.71.xx are used for all data flow.

Thanks.

Regards,

Jeff

[Jon Marshall]

Jeff

I don't uderstand why you are using 172.16.21.x addressing for the IP to serial convertors but the vlans they are in are using 10.1.x.x addressing.

Why can you not assign the IP to serial convertors an address out of the IP subnet used for the vlan they are in ?

Jon

[Jeff Harned]

        Jon

I can change the converters to anything I want.  This is part of the problem.   If we stick with 10.xx.xx.xx adresses that are configured on the switch

now, what addresses can I use on the IP to Serial converters?  

Also with port 15 (VLAN 5) on the switch with the four 172.xx.xx.xx addresses, corresponding to the four Serial to IP modules how would this port

be configured.  This is part of my issue, I do not understand the relationship betwee the 172.xx.xx.xx addresses and the four multicast addreses.

Again I can set this converter to whatever I want.

Thanks.

Regards,

Jeff    

[Jon Marshall]

edited

[Jon Marshall]

Jeff

I can change the converters to anything I want.  This is part of the problem.   If we stick with 10.xx.xx.xx adresses that are configured on the switch now, what addresses can I use on the IP to Serial converters? 

They would simply be assigned an IP from the subnet for that vlan assuming you have spare IPs.  So they would use 10.x.x.x addressing.

Also with port 15 (VLAN 5) on the switch with the four 172.xx.xx.xx addresses, corresponding to the four Serial to IP modules how would this port be configured.  This is part of my issue, I do not understand the relationship betwee the 172.xx.xx.xx addresses and the four multicast addreses..Again I can set this converter to whatever I want.

This is more tricky but if the port is assigned into vlan 5 then you should assign the serial to IP convertors with the corresponding 10.x.x.x addresses from that vlan.

Bear in mind that even though you are using multicast the IP routing table is still used and so it is important to have the right IPs configured.

I would try changing the convertors to use the respective 10.x.x.x addressing and see if that works. If it doesn't then at least we have ruled out something else.

Jon

[Jeff Harned]

   Jon

Well some good news!!  The two receiving units are receiving multicast data at last!!  I have upgraded the last diagram that I sent you with

the updated IP addresses for you to look at and check if they are okay.   I still want to get to the point where I can route between the two VLANS and
I believe the configuration that I sent you yesterday is not correct to accomplish this.

Any comments on the next step to get to this point?

Jon, I appreciate all the help that you have provided!!   

Thanks.

Regards,

Jeff

[Jon Marshall]

Jeff

If the receiving units are getting the multicast stream does that not mean that routing between the vlans is working ie. the source of the multicast stream is on a different vlan than the receivers.

Can you specify what exactly still isn't working ?

Jon

[Jeff Harned]

       Jon

I am looking at this at another angle that may not be incorrect.  Both receivers are configured to each receive 239.1.1.3 and 239.1.15 simultaneously

which is verified through Wireshark and through the LED activity of both receiver units.

I was not perhaps looking at the routing between source and receivers in differnt VLANs but from receiver to reciever in different VLANS and routing

between them.  I am wrong with this?  Is it always Source to Receiver or can routing be done between Receiver Port A and Receiver Port B on a switch?

Thanks.

Regards,

Jeff

[Jon Marshall · Accepted solution]

Jeff

The routing is done between source and receiver in terms of end devices. So if an end device is a receiver it doesn't then route the stream to another receiver.

if you want an end device to receive multiple multicast streams then that end device needs to register for all the streams it wants and the router will then send all streams to the end device.

Does that make sense ?

Jon