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New Member

Multicast general question

I am studying for BSCI and I wanted to see some multicast traffic. I've tried some LIVE radio and TV programs and they are sending data as unicast. What could it be the reason? Could it be an unoptimized setup/topology on they side or could it be something else?

Thanks

9 REPLIES

Re: Multicast general question

You will find that a lot of, if not most, streaming of so-called "live" radio is actually unicast.

One way to generate multicast traffic for lab use is to ping the multicast address from one of your routers. For example ping 239.20.20.20 repeat 100. This ping should also get a response from anything that has joined the IGMP group for that address.

Kevin Dorrell

Luxembourg

Hall of Fame Super Blue

Re: Multicast general question

Kevin

I nearly missed that one. Congratulations on a fantastic achievement and i know this means a lot to you.

Hopefully you won't be deserting us now you are a CCIE.

Jon

Cisco Employee

Re: Multicast general question

Dan,

The Internet, as it stands today, is still mostly unicast only, hence these streams being delivered via unicast.

Regards,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
New Member

Re: Multicast general question

You can also use the mrm tool in IOS to test multicast flows;

http://www.cisco.com/en/US/docs/ios/ipmulti/configuration/guide/imc_routing_monitor_ps6441_TSD_Products_Configuration_Guide_Chapter.html

By the way Kevin, nice to see the CCIE behind your name - congrats once again on your achievement!!!!!

Paul

Cisco Employee

Re: Multicast general question

Thanks Paul for bringing it up. Congratulations Kevin!!! Well done!!!

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

Re: Multicast general question

Thank you Paul and thank you Harold and Jon. It's all down to having colleagues who are patient enough to explain stuff when I didn't understand it. Thank you all, and thanks to all my other colleagues on NetPro over the years. Without you all, I don't think I ever would have made it.

I still have a lot to learn though! I've learned about MRM today!

Kevin Dorrell

(CCIE #20765)

Luxembourg

New Member

Re: Multicast general question

Many Congrats Kevin !!

It has always been very nice to have you around in Netpro. Hope you will still stay and provide your vaulable tips and inputs to all of us.

Very Well done !

Arav

New Member

Re: Multicast general question

Hi there,

Thank you all for you answers !

I have 2 more questions:

1) Why are those streams delivered as unicast and not as multicast? They are well-suited for multicast, aren't they?

2) Can I see multicast traffic on the internet? How can I join as a normal user to a multicast group?

Thanks

Cisco Employee

Re: Multicast general question

Dan,

1) The reason is that multicast capabilities are not ubiquitous in the current Internet. Some providers offer multicast content but it is usually their own and they are very protective of it.

Some streaming applications will attempt to deliver the content via multicast first and will revert to using unicast if the former is not available.

2) You could if your provider offers multicast services and if the source is connected to that same SP or to another SP to which your SP does multicast peering with, either directly or indirectly.

Regards,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
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