Network Ring

Holmes,David A dholmes at
Fri Sep 11 17:26:36 UTC 2009

An additional requirement often overlooked by Metro Ethernet architects
is to ensure that layer 3 multicast stateful protocols are implemented
in the carrier equipment. In order to ensure that PIM (S,G) stateful
packets are not flooded out all ports in customers'
geographically-dispersed switches, PIM snooping must be implemented in
the carrier's equipment. Otherwise, the carriers' Metro Ethernet service
operates like a 1990's-style shared hub incorrectly flooding (S,G)
packets. For customers that have constant 10+ Mbps (S,G) multicast
streams, the absence of PIM snooping effectively renders 10+ Mbps ports

-----Original Message-----
From: ty chan [mailto:chanty_kh at] 
Sent: Friday, September 11, 2009 12:29 AM
To: Rubens Kuhl
Cc: nanog at
Subject: Re: Network Ring

Does anyone have best practise for implementing those technologies ?

I am currently doing a testing LAB with CISCO REP since i have a few
Metro on hand.
It works quite well in my LAB. There is one Request Time Out if the link
break BUT it is physical layer not REP :)

From: Rubens Kuhl <rubensk at>
To: ty chan <chanty_kh at>
Cc: nanog at
Sent: Monday, September 7, 2009 8:15:23 PM
Subject: Re: Network Ring

My vote goes to proprietary ring protection from the vendor you choose:
- EAPS (Extreme)
- REP (Cisco)
- MRP (Foundry/Brocade)
- EPSR (Allied Telesis)

Although EAPS is implemented in all Extreme switches, select models
from the other vendors implement ring protection, but these models
also do other things you might want your network to have (QinQ,
per-VLAN controls).


On Mon, Sep 7, 2009 at 1:14 AM, ty chan<chanty_kh at> wrote:
> Dear all,
> I am in process of planning ring network to cover 15 POPs in City.
Some technologies are chosen for consideration like SDH(Huawei),
PVRST+(Cisco), RSTP(Zyxel), EAPS (extreme network) and MPLS(VPLS). The
purpose is to provide L2 Ethernet connectivities from POPs to central
point (DC) and ring protection.
> I know you all are in those network for years. can you give me some
> Best regards,
> chanty

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