Subject: RE: (*,G) state in PIM-DM

From: vishwas <[email-masked]>
Date: Mon, 16 Nov 98 12:33:00 PST

-----Original Message-----
From: Alejandro Avella [SMTP:[email-masked]]
Sent: Monday, November 16, 1998 9:17 AM
To: PIM LIST
Subject: (*,G) state in PIM-DM

Hi everyone,

PIM-DM only uses source trees (no shared trees are used).  However, in
PIM-DM,
(*,G) entries are created automatically as soon as the first packet
(from any source)
arrives for group "G" or when a locally connected host has joined the
group via IGMP.  [1]

Question: I think there is no need to create this (*,G) entry.  It seems

like a duplicate entry in the table that is not needed.  Is this
correct?
If not, what is the purpose of the (*,G) entry?

(*,G) entries are used  in sparse mode to create shared trees,
but it does not make sense to me to have this entry in dense mode (I
think).

Cheers,

 -Alejandro

[1] ftp://ftp-eng.cisco.com/ipmulticast/training/Module3.pdf

[vishwas]

An (S,G) entry will be created only when the mcast data arrives. And IT   
IS NOT CREATED BY JUST JOINS FROM HOSTS, whilst data hasent arrived yet.

I dont thik (*,G) state will be created in PIM-DM any way. Which section   
of the draft UR refering to...?

Regards
Vishwanath S. Edavayyanamath
 --------------------------------------------------------------------------  
 ------------------------
Software Engineer, Future Software Pvt. Ltd, Chennai, India
Ph : +91-44-4330550 (335)
Private e-mail : [email-masked]

---

From: Alejandro Avella <[email-masked]>
Date: Mon, 16 Nov 1998 07:32:03 -0700

Vishwas,

> IS NOT CREATED BY JUST JOINS FROM HOSTS, whilst data hasent arrived yet.

The draft does not say that but the tutorial from Cisco says that in page 25.
See ftp://ftp-eng.cisco.com/ipmulticast/training/Module3.pdf

> of the draft UR refering to...?

Again the draft does not say that but the tutorial from Cisco says that in
page 25.

Maybe, my confusion comes from an error in the Cisco Tutorial. Can someone
confirm that the Cisco tutorial is incorrect?

-Alejandro

---

From: Chirayu Shah <[email-masked]>
Date: Mon, 16 Nov 1998 11:08:47 -0500

>-Alejandro

Alejandro,

Cisco's PIM-DM implementation creates a (*,G) state for some reason.
But I don't think it is necessary.

Chirayu.

---

From: Bill Fenner <[email-masked]>
Date: Mon, 16 Nov 1998 14:14:11 PST

>confirm that the Cisco tutorial is incorrect?

The cisco tutorial is not purely about PIM-DM; it's about cisco's
implementation.  cisco's implementation may create (*,G) state but
that doesn't mean that it's a requirement.

  Bill