Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Intervlan Multicast on a 4510r

We have a 4510r as our distribution switch. Recently we have been asked to enable ip multicast so that some network projectors can be discovered by laptops in different vlans. At this moment the requirement does not grow beyond that. We have 3560s in the access layer and the afroementioned 4510 in the distribution. So I'm not touching my core layer at all  The 3 vlans in question are all defined on the 4510.

On the 4510 I did a:

ip multicast-routing   in global config, and then on the three vlan interfaces in question I did a:

ip pim dense-mode.

Is there anything else that I should need to do? I can ping the multicast group addr ( 239.255.255.250) and I get a bunch of responses but I don't see anything from the device I am trying to discover.

I can see a last reporter from that group in that vlan ( 241). There are two projectors, 192.168.241.10, and .11

sh ip igmp groups

IGMP Connected Group Membership

Group Address    Interface                Uptime    Expires   Last Reporter

239.255.255.253  Vlan216                  01:39:23  00:02:24  0.0.0.0

239.255.255.250  Vlan212                  03:22:14  00:02:25  192.168.212.128

239.255.255.250  Vlan216                  03:22:33  00:02:17  192.168.216.10

239.255.255.250  Vlan241                  03:22:54  00:02:17  192.168.241.10

239.255.255.246  Vlan216                  01:39:24  00:02:17  192.168.216.10

234.5.6.8        Vlan216                  00:00:59  00:02:17  192.168.216.10

226.178.217.5    Vlan212                  01:42:00  00:02:27  192.168.212.15

232.44.44.233    Vlan212                  03:22:13  00:02:25  192.168.212.10

232.44.44.233    Vlan216                  03:22:33  00:02:17  192.168.216.10

239.77.124.213   Vlan216                  03:22:33  00:02:17  192.168.216.10

224.0.1.60       Vlan216                  00:02:16  00:02:17  192.168.216.10

224.0.1.40       Vlan241                  03:22:18  00:02:20  192.168.241.1

Here is my sh ip mroute:

sh ip mroute

IP Multicast Routing Table

Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,

       L - Local, P - Pruned, R - RP-bit set, F - Register flag,

       T - SPT-bit set, J - Join SPT, M - MSDP created entry,

       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,

       U - URD, I - Received Source Specific Host Report,

       Z - Multicast Tunnel, z - MDT-data group sender,

       Y - Joined MDT-data group, y - Sending to MDT-data group

Outgoing interface flags: H - Hardware switched, A - Assert winner

Timers: Uptime/Expires

Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 239.255.255.253), 00:07:46/00:01:15, RP 0.0.0.0, flags: DC

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan216, Forward/Dense, 00:07:46/00:00:00

(*, 239.255.255.250), 00:09:54/00:02:16, RP 0.0.0.0, flags: DC

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan212, Forward/Dense, 00:09:54/00:00:00

    Vlan216, Forward/Dense, 00:09:54/00:00:00

    Vlan241, Forward/Dense, 00:09:54/00:00:00

(*, 239.255.255.246), 00:09:49/00:02:10, RP 0.0.0.0, flags: DC

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan216, Forward/Dense, 00:09:49/00:00:00

(*, 234.5.6.8), 00:10:17/stopped, RP 0.0.0.0, flags: DC

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan216, Forward/Dense, 00:02:09/00:00:00

(192.168.217.18, 234.5.6.8), 00:00:17/00:02:42, flags: PT

  Incoming interface: Vlan216, RPF nbr 0.0.0.0

  Outgoing interface list: Null

(*, 226.178.217.5), 00:10:13/stopped, RP 0.0.0.0, flags: DC

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan212, Forward/Dense, 00:10:13/00:00:00

(192.168.212.15, 226.178.217.5), 00:00:13/00:02:46, flags: PT

  Incoming interface: Vlan212, RPF nbr 0.0.0.0

  Outgoing interface list: Null

(*, 232.44.44.233), 00:09:49/00:02:16, RP 0.0.0.0, flags: DC

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan212, Forward/Dense, 00:09:49/00:00:00

    Vlan216, Forward/Dense, 00:09:49/00:00:00

(*, 239.77.124.213), 00:09:49/00:02:10, RP 0.0.0.0, flags: DC

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan216, Forward/Dense, 00:09:49/00:00:00

(*, 224.0.1.60), 00:10:07/00:02:56, RP 0.0.0.0, flags: DC

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan216, Forward/Dense, 00:03:26/00:00:00

(*, 224.0.1.40), 00:10:29/00:02:09, RP 0.0.0.0, flags: DCL

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan241, Forward/Dense, 00:10:29/00:00:00

AND pim interface:

sh ip pim inter

Address          Interface                Ver/   Nbr    Query  DR     DR

                                          Mode   Count  Intvl  Prior

192.168.241.1    Vlan241                  v2/D   0      30     1      192.168.241.1

192.168.216.1    Vlan216                  v2/D   0      30     1      192.168.216.1

192.168.212.1    Vlan212                  v2/D   0      30     1      192.168.212.1

This is pretty new to me, so not sure if I am missing something obvious.

Any suggestions?

1 ACCEPTED SOLUTION

Accepted Solutions
Hall of Fame Super Blue

Re: Intervlan Multicast on a 4510r

Don

It needs to be greater than 1 to account for the L3 hop between vlans. 

So it needs to be 2 or more for it to work across vlans.

Jon

35 REPLIES
Hall of Fame Super Blue

Intervlan Multicast on a 4510r

Don

There is nothing missing from your configuration (assuming IGMP snooping is enabled but it is usually on by default).

Do the network projectors generate a multicast stream ?

If you look at your "sh ip mroute" output for the multicast group you are interested there is only a (*, 239.255.255.250) entry. What you should be seeing with pim dense mode is a (, 239.255.255.250) entry where source IP is one of the projectors.

That stream is then flooded to any vlans that have registered an interest in the stream with IGMP requests ie. laptops in vlans 212 and 216.

It doesn't look from your outputs as though the projectors are actually generating a multicast stream.

Jon

New Member

Re: Intervlan Multicast on a 4510r

Thanks. That is sort of what I was thinking. I am told that the projectors use WSD ( Web Services on Devices) which uses multicast for discovery. But I've been banging my head on the wall today trying to figure out why this won't work. It works locally, as I mentioned, if both devices are in the same vlan.

The projectors are an appliance being built and designed here and the inside is a Windows 8 I believe. So it's the windows network projector discovery service that I'm trying to get working. I believe that uses WSD for discovery...

Hall of Fame Super Blue

Re: Intervlan Multicast on a 4510r

Don

It works locally, as I mentioned, if both devices are in the same vlan.

That is strange as it should work across vlans. Can you check that the TTL in the multicast packets are > 1 ie. the TTL needs to account for the L3 hop to the laptop vlans.

The TTL setting would be within the application settings on the projectors ie. nothing to do with the switch(es).

Jon

New Member

Re: Intervlan Multicast on a 4510r

Thanks again for the response, I will need to have someone get that information from the dev team that is building that product.

Re: Intervlan Multicast on a 4510r

Hello

can you post the following  from the switches active in MC

sh ip pim neighbors

sh ip pim interface count

sh ip pim rp-mapping

res

Paul

Please don't forget to rate any posts that have been helpful.

Thanks.

Please don't forget to rate any posts that have been helpful. Thanks.
New Member

Intervlan Multicast on a 4510r

There is really only one switch active in MC. All access layer switches are 3560's that are only doing L2. The routing is done on the 4510 between the vlan interfaces.   I did run the commands on one of the 3560s but there was no output at all.

Here is the output from the 4510:

sh ip pim nei

PIM Neighbor Table

Mode: B - Bidir Capable, DR - Designated Router, N - Default DR Priority,

      S - State Refresh Capable

Neighbor          Interface                Uptime/Expires    Ver   DR

Address                                                            Prio/Mode

ktsw-B-distribution#sh ip pim interface count

State: * - Fast Switched, D - Distributed Fast Switched

       H - Hardware Switching Enabled

Address          Interface                FS  Mpackets In/Out

192.168.241.1    Vlan241                  * H 3006/83

192.168.216.1    Vlan216                  * H 239307/49

192.168.212.1    Vlan212                  * H 1111925/16

ktsw-B-distribution#

ktsw-B-distribution#show ip pim rp mapping

PIM Group-to-RP Mappings

This is PIM-DM, though, so would there be RP mappings?

Re: Intervlan Multicast on a 4510r

Hello

Sorry to ask this - Do you have ip routing enabled on the core and any of the access switches?

I have labbed this up the best i could- please see the results:

core switch:

snooping enabled by default

ip multicast-routing distributed

pim dense mode enabled on SV'sI

sh ip pim interface | in Vlan

192.168.212.1    Vlan212                  v2/D   0      30     1      192.168.212.1

192.168.216.1    Vlan216                  v2/D   0      30     1      192.168.216.1

192.168.241.1    Vlan241                  v2/D   0      30     1      192.168.241.1

Core#sh ip mroute | b In

Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 239.255.255.250), 00:00:37/00:02:32, RP 0.0.0.0, flags: DCL

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan212, Forward/Dense, 00:00:37/00:00:00

(*, 239.255.255.246), 00:00:37/00:02:33, RP 0.0.0.0, flags: DCL

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan216, Forward/Dense, 00:00:37/00:00:00

(*, 234.5.6.8), 00:00:37/00:02:34, RP 0.0.0.0, flags: DCL

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan241, Forward/Dense, 00:00:38/00:00:00

Host (192.168.212.10 - vlan 212 -  attached to access switch)

Host#ping 234.5.6.8 repeat 5

Reply to request 0 from 192.168.212.1, 4 ms

Reply to request 1 from 192.168.212.1, 1 ms

Host#ping  239.255.255.246 repeat 2

Reply to request 0 from 192.168.212.1, 1 ms

Reply to request 1 from 192.168.212.1, 1 ms

core

Corew#sh ip mroute | in  192.168.212.10

(192.168.212.10, 239.255.255.246), 00:02:20/00:00:48, flags: LT

(192.168.212.10, 234.5.6.8), 00:02:48/00:00:29, flags: LT

The only time I produced the similar output to yourself was when I disabled ip routing on the core and ping the MC address residing on the same vlan.

Host#ping  239.255.255.250 repeat 2

Reply to request 0 from 192.168.212.1, 4 ms

Reply to request 1 from 192.168.212.1, 1 ms

core

sh ip mroute | b In

Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 239.255.255.250), 00:04:06/00:02:18, RP 0.0.0.0, flags: DCL

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan212, Forward/Dense, 00:04:06/00:00:00

I doubt you would have ip routing disabled on a core switch but is it enabled on any of the access switches also, if not than I agree with Jon that the problem looks like its originating from the source of the MC flow.

res

Paul

Please don't forget to rate any posts that have been helpful.

Thanks.

Please don't forget to rate any posts that have been helpful. Thanks.
Hall of Fame Super Blue

Re: Intervlan Multicast on a 4510r

Paul

I may be misunderstading but IP routing does not need to be enabled on the access switches, only on the core.

The issue is that there is no source specific multicast group entry for the stream.

I suspect this may be an issue with how the projectors actually use multicast. It works on the same LAN but not across L3 hops which suggets a TTL issue but i am not entirely sure how it is meant to work.

Jon

Re: Intervlan Multicast on a 4510r

Hello Jon

Yes you are correct - Just to verify - I didn't mean to suggest ip routing is required on the access switches maybe it was the way I posted my reply -

what I was trying to say is that if IP routing was enabled by mistake on the access switches or it wasn't enabled on the core, Then lab test I performed produced a similar output to the OP in that, the mroute table of the core switch regards showing no actual MC source being reported.

Apologies to all if my post was a bit misleading

res

Paul

Please don't forget to rate any posts that have been helpful.

Thanks.

Please don't forget to rate any posts that have been helpful. Thanks.
Hall of Fame Super Blue

Re: Intervlan Multicast on a 4510r

Hi Paul

what I was trying to say is that if IP routing was enabled by mistake on the access switches or it wasn't enabled on the core

my mistake not yours. I should have read your post more carefully.

Hadn't had my first cup of coffee of the day

Jon

New Member

Re: Intervlan Multicast on a 4510r

Hi.

Routing is not enabled on the access switches. Routing is enabled on the 4510r.  I can ping the multicast addr in question ( 239.255.255.250) from the 4510 and I get many responses ( mostly printers and such), but nothing from the projectors. I can see the projectors in the igmp groups command output, but cannot ping them. Multicast is only used by the projectors for discovery purposes, so I'm told. So if you use the Windows "Connect to a Network Projector" it will use that multicast addr and udp/3702 to discover any Windows Network Projectors on the network. This works on the same segment, but does not seem to want to cross vlans right now.

One small note, I only did a ip multicast-routing on the 4510r, not a ip mulitcast-routing distributed command.

New Member

Re: Intervlan Multicast on a 4510r

Here is the output, just now, of an show ip mroute, sh ip igmp groups, and a MC ping to 239.255.255.250. I can see one of the projectors ( 192.168.241.11) in the igmp groups, but it does not show up in a MC ping, nor can I discover it across vlans.

ktsw-B-distribution#sh ip mroute

IP Multicast Routing Table

Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,

       L - Local, P - Pruned, R - RP-bit set, F - Register flag,

       T - SPT-bit set, J - Join SPT, M - MSDP created entry,

       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,

       U - URD, I - Received Source Specific Host Report,

       Z - Multicast Tunnel, z - MDT-data group sender,

       Y - Joined MDT-data group, y - Sending to MDT-data group

Outgoing interface flags: H - Hardware switched, A - Assert winner

Timers: Uptime/Expires

Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 239.255.255.250), 17:41:15/00:02:30, RP 0.0.0.0, flags: DC

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan212, Forward/Dense, 17:41:15/00:00:00

    Vlan241, Forward/Dense, 17:41:15/00:00:00

(*, 226.178.217.5), 17:41:34/stopped, RP 0.0.0.0, flags: DC

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan212, Forward/Dense, 17:41:34/00:00:00

(192.168.212.15, 226.178.217.5), 00:01:37/00:01:22, flags: PT

  Incoming interface: Vlan212, RPF nbr 0.0.0.0

  Outgoing interface list: Null

(*, 232.44.44.233), 17:41:09/00:02:30, RP 0.0.0.0, flags: DC

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan212, Forward/Dense, 17:41:09/00:00:00

(*, 224.0.1.40), 17:41:48/00:02:09, RP 0.0.0.0, flags: DCL

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan241, Forward/Dense, 17:41:48/00:00:00

ktsw-B-distribution#sh ip igmp groups

IGMP Connected Group Membership

Group Address    Interface                Uptime    Expires   Last Reporter

239.255.255.250  Vlan212                  20:54:52  00:02:22  192.168.212.150

239.255.255.250  Vlan241                  20:55:33  00:02:53  192.168.241.11

226.178.217.5    Vlan212                  19:14:38  00:02:23  192.168.212.15

232.44.44.233    Vlan212                  20:54:52  00:02:21  192.168.212.138

224.0.1.40       Vlan241                  20:54:56  00:02:55  192.168.241.1

ktsw-B-distribution#ping 239.255.255.250

Type escape sequence to abort.

Sending 1, 100-byte ICMP Echos to 239.255.255.250, timeout is 2 seconds:

Reply to request 0 from 131.194.168.192.in-addr.arpa.fqdn.unknown.com (192.168.194.131), 8 ms

Reply to request 0 from sales-mfp.cds,int (192.168.228.106), 8 ms

Reply to request 0 from 192.168.194.19, 8 ms

Reply to request 0 from exec-mp201.cds.int (192.168.197.106), 8 ms

Reply to request 0 from 192.168.194.124, 8 ms

Reply to request 0 from 192.168.194.199, 8 ms

Reply to request 0 from 192.168.194.145, 8 ms

Reply to request 0 from 192.168.194.191, 8 ms

Reply to request 0 from 192.168.194.135, 8 ms

Reply to request 0 from 192.168.194.177, 8 ms

Reply to request 0 from 192.168.194.129, 8 ms

Reply to request 0 from 192.168.194.148, 8 ms

Reply to request 0 from 192.168.194.171, 8 ms

Reply to request 0 from 192.168.194.202, 8 ms

Reply to request 0 from 192.168.194.120, 8 ms

Reply to request 0 from 192.168.194.136, 8 ms

Reply to request 0 from 192.168.194.146, 8 ms

Reply to request 0 from 192.168.194.20, 8 ms

Reply to request 0 from 192.168.194.188, 8 ms

Reply to request 0 from ve4-mfp.cds.int (192.168.194.112), 8 ms

Reply to request 0 from ve-exec-mfp.cds.int (192.168.194.115), 8 ms

Reply to request 0 from cmh-mfp.cds.int (192.168.194.114), 8 ms

Reply to request 0 from ve3-mfp.cds.int (192.168.194.113), 8 ms

Reply to request 0 from 192.168.194.176, 8 ms

Reply to request 0 from 192.168.194.139, 8 ms

Reply to request 0 from 192.168.194.128, 8 ms

ktsw-B-distribution#

New Member

Re: Intervlan Multicast on a 4510r

I can confirm that MC is working across vlans in general as the vlan that had most of the devices in it, printers and such, did not have a pim command on it as I did not want it participating in MC. But for test purposes I just put a ip pim dense-mode on that SVI and was then able to do a successful MC ping from my workstation that resides in another pim enabled vlan. So at least I know that MC routing in general should work with my setup.

Hall of Fame Super Blue

Re: Intervlan Multicast on a 4510r

Don

With pim dense mode the important entry in your mroute is the one with a source IP as well as the group ie. not this one -

(*, 239.255.255.250), 17:41:15/00:02:30, RP 0.0.0.0, flags: DC

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan212, Forward/Dense, 17:41:15/00:00:00

    Vlan241, Forward/Dense, 17:41:15/00:00:00

as you can see there is no source IP ie. just a * entry. For multicast routing to work there must be a stream to route ie. IGMP queries are not routed, only the actual stream. But from your outputs there is no stream.

I did a bit of hunting on Miscrosoft's site on Web Services on Devices and i found this where it suggests there are two ways for clients to discover devices -

The Web Services on Devices stack and API (WSDAPI) implementation provides the following discovery mechanisms, each of which can allow a client application to find and access a device host.

Service availability multicast
The device host uses UDP to multicast a service availability message. This message cannot make use of a secure channel, so this type of service discovery does not support authentication. The WSDAPI implementation does not offer authentication, however, the WS-Discovery specification provides an avenue for authentication. Typically, the multicast message does not traverse IP routers, so only the client applications on the same subnet as the device host can receive the service availability multicast.

Directed discovery
The client application uses TCP to send a directed discovery message. This message can make use of a secure channel, so this mechanism supports authentication. Also, these messages can traverse an IP router, so this mechanism allows client applications to discover a device hosts that is located on a remote subnet.

So from the above when using multicast mode  i would expect the projector (the device host) to multicast out a message and this would then be multicast routed by your switch onto those vlans that the switch received IGMP queries.from. 

Perhaps within the same vlan they were using the other method where they sent a TCP packet to discover the projector ?

Either way i don't think it is the switch configuration, it is to with the projectors and whether or not they generate a multicast stream for your switch to forward.

Jon

New Member

Re: Intervlan Multicast on a 4510r

Thanks for the reply Jon. I guess I may have to start capturing some packets to get to the bottom of this. I am curious about the TCP directed discovery mentioned by MS.  If the devices are using that method, then it is not crossing a router either since no discovery is happening across vlans right now.

Hall of Fame Super Blue

Intervlan Multicast on a 4510r

Don

If the devices are using that method, then it is not crossing a router either since no discovery is happening across vlans right now.

Good point.

I would try, as you say, capturing packets coming from the projectors.

Jon

New Member

Re: Intervlan Multicast on a 4510r

What I find interesting is that I just put my laptop switchport into the projector vlan, 241. Assigned myself a static addr there and confirmed that I can ping the projectors, 241.10 and 241.11, however I get no response from a ping to the multicast address that they are supposed to be using?  I should see a response, no?

C:\>ping 192.168.241.10

Pinging 192.168.241.10 with 32 bytes of data:

Reply from 192.168.241.10: bytes=32 time<1ms TTL=128

Reply from 192.168.241.10: bytes=32 time<1ms TTL=128

Reply from 192.168.241.10: bytes=32 time<1ms TTL=128

Reply from 192.168.241.10: bytes=32 time<1ms TTL=128

Ping statistics for 192.168.241.10:

    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),

Approximate round trip times in milli-seconds:

    Minimum = 0ms, Maximum = 0ms, Average = 0ms

C:\>ping 192.168.241.11

Pinging 192.168.241.11 with 32 bytes of data:

Reply from 192.168.241.11: bytes=32 time<1ms TTL=128

Reply from 192.168.241.11: bytes=32 time<1ms TTL=128

Reply from 192.168.241.11: bytes=32 time<1ms TTL=128

Reply from 192.168.241.11: bytes=32 time<1ms TTL=128

Ping statistics for 192.168.241.11:

    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),

Approximate round trip times in milli-seconds:

    Minimum = 0ms, Maximum = 0ms, Average = 0ms

C:\>ping 239.255.255.250

Pinging 239.255.255.250 with 32 bytes of data:

Request timed out.

Request timed out.

Request timed out.

Request timed out.

Ping statistics for 239.255.255.250:

    Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

C:\>

At least now I can easily do a wireshark of the successful discovery process.

Re: Intervlan Multicast on a 4510r

Hello
Yes you should be able too.

These mc groups are attached in specific interfaces. And are these interfaces directly attached to the core switch or on an access switch.

Do they have pim specifically assigned?

Res
Paul



Sent from Cisco Technical Support iPad App

Please don't forget to rate any posts that have been helpful. Thanks.
New Member

Re: Intervlan Multicast on a 4510r

Yes, the topology is pretty simple actually. A network projector device ( runs a version of windows 8 I believe in a 1U rack mount chassis) is connected to a 3560 with no routing enabled. The 3560 is connected to a 4510r that is our distribution switch. Routing is enabled here. Ip multicast is enabled here. The vlan interfaces that I want to participate in multicast have ip pim dense-mode command applied.

I just did a wireshark of a workstation trying to discover and used a port span on the 3560 with a sniffer attached locally to capture the packets of the projector device. I do not see any 239.255.255.250/udp 3702 at all being received by the projector device. If I run the same thing but with a workstation in the same vlan as the projector, I do see the multicast discovery packets occurring. So it seems something is preventing the multicast from crossing vlans.

Hall of Fame Super Blue

Intervlan Multicast on a 4510r

Don

I maybe misunderstanding here but it sounds like you are expecting the client packets to be routed between vlans and i don't think that is how it is meant to work.

Apologies if i have got what you are saying wrong but if you look back at my previous post where i copied that information from the Microsoft site it says that it is the device ie. the projector that sends the multicast  as a service availability message.

So it's not that the projector receives this multicast group from the clients. It is the projector that is meant to generate that message. The clients simply register their interest in the message with the switch using IGMP and then the switch, when it receives the multicast message sends it to any vlans where clients have registered their interest.

Jon

New Member

Re: Intervlan Multicast on a 4510r

Maybe I am not understanding it properly. The device development team came to us and said we need this device to be discoverable on the network and it uses multicast for that...we think. So I looked up that it uses WSD for the discovery process which uses multicast 239.255.255.250/udp 3702  When I do a discovery on the same segment I do see that udp traffic with a destination of 239.255.255.250 during the discovery process. When I attempt that same process from a different vlan, I see the source attempting to send to that destination, 239.255.255.250 but I never see anything arrive on the projector end.

Am I incorrect in thinking that I should?

I could share the .cap files but that might be out of the scope of this forum?

Hall of Fame Super Blue

Intervlan Multicast on a 4510r

Don

It may well be me that is misuderstanding. It sounds like it is actually the laptop that generates the multicast stream and the projector simply registers to receive it.

But that isn't what the Microsoft paper i read is saying ie. it suggests it is the projector that should be sending traffic to this multicast addess which would make sense to me because then any client that was interested could simply register. If it was for the client to discover the projector then what use would multicast be ie. you simply use the TCP based discovery mechanism.

The idea behind using the multicast solution is so each client does not send their own TCP messages independantly of each other. The projector simply sends out a multicast message and all clients can receive this.

I will do some more hunting around.

Have you looked at the projector configuration settings to see if there is anything obvious that can be set/changed ?

Jon

New Member

Re: Intervlan Multicast on a 4510r

Hi Jon, thanks again for you interest and time in this thread.

According to this article (

http://msdn.microsoft.com/en-us/library/dd352335.aspx), :

The WS-Discovery protocol uses SOAP and UDP (User Datagram Protocol) multicast to enable services to be discovered by a client. In the RFID world, services discovered are RFID devices and the client is a provider. WS-Discovery has four types of messages:

  • Hello. A service sends a Hello message by using UDP multicast when it joins a network.

  • Bye. A service sends a Bye message when it prepares to leave the network.

  • Probe. A client sends a Probe message by using UDP multicast looking for services it is interested in. Matching services respond with ProbeMatch messages.

  • Resolve. A client sends a Resolve message by using UDP multicast to find out transport addresses for services. Matching services respond with ResolveMatch messages.

The multicast address used is 239.255.255.250 on IPV4 networks and [FF02::C] on IPV6 networks. In both cases, multicast messages are sent to port 3702. Several components in Windows Vista such as "People Near Me" and "Computers Near Me" use the WS-Discovery protocol. The detailed specification for the WS-Discovery protocol can be found athttp://go.microsoft.com/fwlink/?LinkId=107376.

Hall of Fame Super Blue

Intervlan Multicast on a 4510r

Don

Can you try from a client in a different vlan from the projectors and then post the output of "sh ip mroute" together with the client IP address.

Jon

New Member

Re: Intervlan Multicast on a 4510r

Sure, I did that earlier and captured the packets as well. I will run it again now:

Client ip addr 192.168.212.144

ktsw-B-distribution#sh ip mroute

IP Multicast Routing Table

Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,

       L - Local, P - Pruned, R - RP-bit set, F - Register flag,

       T - SPT-bit set, J - Join SPT, M - MSDP created entry,

       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,

       U - URD, I - Received Source Specific Host Report,

       Z - Multicast Tunnel, z - MDT-data group sender,

       Y - Joined MDT-data group, y - Sending to MDT-data group

Outgoing interface flags: H - Hardware switched, A - Assert winner

Timers: Uptime/Expires

Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 239.255.255.250), 22:14:47/00:02:55, RP 0.0.0.0, flags: DC

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan216, Forward/Dense, 02:29:41/00:00:00

    Vlan212, Forward/Dense, 22:14:47/00:00:00

    Vlan241, Forward/Dense, 22:14:47/00:00:00

(*, 226.178.217.5), 22:15:06/stopped, RP 0.0.0.0, flags: DC

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan241, Forward/Dense, 03:03:08/00:00:00

(192.168.241.120, 226.178.217.5), 00:00:10/00:02:49, flags: PT

  Incoming interface: Vlan241, RPF nbr 0.0.0.0

  Outgoing interface list: Null

(*, 232.44.44.233), 22:14:41/00:02:55, RP 0.0.0.0, flags: DC

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan212, Forward/Dense, 22:14:41/00:00:00

(*, 224.0.1.40), 22:15:20/00:02:30, RP 0.0.0.0, flags: DCL

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list:

    Vlan241, Forward/Dense, 22:15:20/00:00:00

ktsw-B-distribution#

New Member

Re: Intervlan Multicast on a 4510r

In your note above I see that MS mentions two methods: multicast discovery ( for local segments); and TCP directed. I assume that correlates to the two options one sees when one opens the Connect to a Network Projector wizard in Windows. One is to search for projectors and the other option is to put in an ip addr.

Our product team do not wish to have to put in an ip address when they demo this device on our premises. That is why they are pushing for us to make it searchable over the network.  It seems to me that it should be doable, if not preferrable?

Hall of Fame Super Blue

Intervlan Multicast on a 4510r

Don

Is there anyway to check the TTL of the packets. What do the captures show ?

Jon

New Member

Re: Intervlan Multicast on a 4510r

Seems it is 1?

cap.png

Hall of Fame Super Blue

Re: Intervlan Multicast on a 4510r

Don

It needs to be greater than 1 to account for the L3 hop between vlans. 

So it needs to be 2 or more for it to work across vlans.

Jon

963
Views
0
Helpful
35
Replies
CreatePlease login to create content