Multicast Routing between VLANs

MD-Consulting · ‎02-02-2015

Dear all,

i am heaving serious trouble with multicast routing, in speciall...with Apple Bonjour.

Here is the Topology:

Nexus5596UP (with L3-Card) ---connected via PortChannel ---> Cisco 3850 (pure Layer2)

The Nexus is the Core-Router for every VLAN. VLAN 107 is the SharedApple VLAN which hosts the Apple AirportExpress. VLAN 114 is a Client VLAN where an ITunes Client try's to stream to the AirportExpress in VLAN107.

If the Client is in the same VLAN like the AirportExpress it works fine, but not if he is in VLAN114. Within the same VLAN, a ping to 224.0.0.251 is successful, connected to VLAN114 it is not.

IGMP is activated by default, thats why it is working within the same VLAN ( no routing needed).

Here is the config of the Nexus Switch:

feature telnet
cfs ipv4 distribute
cfs eth distribute
feature ospf
feature pim
feature msdp
feature eigrp
feature interface-vlan
feature hsrp
feature lacp
feature dhcp
feature vpc
feature lldp

ip pim rp-address 1.1.1.1 group-list 224.0.0.0/4
ip pim ssm range 232.0.0.0/8

vlan 107
name SharedApple

vlan 114
name Owner

spanning-tree vlan 1-3967, 4048-4093 priority 4096
service dhcp
ip dhcp relay

interface Vlan107
description SharedApple
no shutdown
no ip redirects
ip address 10.7.107.1/24
ip pim sparse-mode

interface Vlan114
description Owner-Network
no shutdown
no ip redirects
ip pim sparse-mode
ip address 10.7.114.1/24

interface loopback100
description Airplay
ip address 1.1.1.1/32
ip pim sparse-mode

I can not believe I am the only one who try to route Apple Bonjour.... Please help :)

Cheers

Thorsten

mlund · ‎02-03-2015

Hi Thorsten

You are using 224.0.0.251 as the mcast address, this will not work because the hole 224.0.0.x is reserved for local use only, and will not be routed.

Try with addresses in the 239.x.y.z instead

/Mikael

MD-Consulting · ‎03-21-2015

Sorry for the late response, it were very 8 busy weeks!

I trieed the Bonjour proxy, which worked fine, but I was not really happy with it.

So I tried to give it a go with the WLC5760. What should I say, it works like a charm, even with rules that one vlan can see both Airplay devices ( they are in different vlans) and another vlan can only one of the Airplay devices.

The bad thing on it is, not everything can be done from the GUI, so it is half doing it in GUI and half in shell ( or completely in shell), so please Cisco do not start like Microsoft!! Either doing everything in the GUI or shell but not a mix!

If some one is interested in how I realized it, feel free to post it or send me a messages and I will post the configuration.

Thanks for all the help guys!!

Cheers

Thorsten

Bilal Nawaz · ‎02-03-2015

Hello Thorsten, as mentioned by Mikael the mcast address range 224.0.0.0 - 224.0.0.255 are individually assigned by IANA reserved for multicasting on the local network only. Examples of this are like OSPF which uses 224.0.0.5 and 224.0.0.6, RIPv2 using 224.0.0.9. These are not to be routed.

The 239.0.0.0/8 range defined by RFC 2365 is for private use within an organisation.

Apart from this, I think the config is fine.

See here: http://www.iana.org/assignments/multicast-addresses/multicast-addresses.txt

hth

Please rate useful posts & remember to mark any solved questions as answered. Thank you.

Jon Marshall · ‎02-03-2015

Thorsten

Mikael seems to be suggesting you can change the multicast address being used by Bonjour in which case that would be a solution.

But I'm not sure you can do this, although happy to be proved wrong.

The issue as pointed out is that Bonjour uses a 224.0.0.x multicast group address and these are considered link local ie. not to be routed.

I haven't needed to do this myself but most definitely you aren't the only one and yes it is problematic.

Have a read of this link which apparently shows you how to get it working. It's also worth reading the comments section at the end as there are a number of doubts as to whether it does work but the author says he has it working on a production network -

http://packetpushers.net/multicasting-apples-bonjour-protocol/

Jon

MD-Consulting · ‎02-03-2015

Hey all,

thanks for the replays first of all!!

Jon, you are right you can not change the way how Bonjour is advertising its services, I opend up a Cisco TAC 2 weeks ago and all I heard from all 4 Engineers working on it was "It should work now."

But actually it wasn't :(

THe strange thing is, that I did the same stuff on other projects but with different Cisco hardware. We used a 6506 instead of the Nexus and all I had to was enable multicast routing with

ip multicast-routing

enable IGMP snooping

enable PIM sparse/sparse-dense mode on the particular SVI's and it worked like a charm. Even on the WLC5508 after enabling MDNS all worked as it should.

Any ideas if the two Core technologies behave different in multicast routing?

If you do a sh ip mroute then you can see outgoing interface vl114 and 107 joined into the 239.255.255.250 but I guess this is nothing the Apple stuff can handle.....

Maybe I found another solution without the need of having multicast routing configured, I will try a Bonjour proxy based on Linuk called avahi . I tryed it at home yesterday and it was working perfectly but I can ealiest test it out on thursday.

Hopefully I can then abstain from mutlicast routing for only Bonjour working in the network.

Thanks for all the answers, I will give it a try with the Bonjour proxy and will post it if works out or not.

Cheers

Thorsten