Subject: re: possible scope gap//re: [nvo3] L2VPN overlap?

From: Xuxiaohu <[email-masked]>
Date: Fri, 14 Oct 2011 02:47:51 +0000

There is a mistake that I should correct. That is Data Center Mobility (http://datatracker.ietf.org/doc/draft-raggarwa-data-center-mobility) still uses L2 overlay (i.e., MAC-based forwarding ) to connect VMs which are belong to the same subnet, and host routes are only used for inter-subnet communication.

Best regards,
Xiaohu

发件人: Xuxiaohu
发送时间: 2011年10月9日 10:45
收件人: 'Murari Sridharan'; Thomas Narten; [email-masked]
抄送: [email-masked]; [email-masked]'
主题: possible scope gap//re: [nvo3] L2VPN overlap?

It is a good question.

IMHO, It’s absolutely possible to realize network virtualization in a data center or across multiple data centers by using L3 overlay, especially host route based IP-only L2VPN service. Host route based IP-only L2VPN service could also allow the hosts within a give VPN instance to act as if they were located within a subnet/LAN except that only IP traffic is supported. Compared to those MAC forwarding based L2VPN services (i.e., L2 overlay) such as VPLS,  host route based IP-only L2VPN service does seem a bit restrictive since those legacy non-IP applications (e.g., link-local multicast, non-IP unicast) would not be supported. However, host based IP-only L2VPN service has many unique and charming advantages in addressing the scaling issues that today’s cloud data centers are facing, such as ARP broadcast storm reduction, unknown unicast flooding avoidance, MAC table reduction on CE switches, active-active DC exit and ARP table reduction on DC exit routers...

Examples of such approach are:
Virtual Subnet (http://tools.ietf.org/html/draft-xu-virtual-subnet-06)
Data Center Mobility (http://datatracker.ietf.org/doc/draft-raggarwa-data-center-mobility)
VL2(http://research.microsoft.com/apps/pubs/default.aspx?id=80693)

Best regards,
Xiaohu

发件人: [email-masked] [mailto:[email-masked]] 代表 Murari Sridharan
发送时间: 2011年10月4日 12:43
收件人: Thomas Narten; [email-masked]
主题: Re: [nvo3] L2VPN overlap?

Why are we restricting the discussion to just L2 overlays? The virtual topology can be L3 as well.

Sent from my Windows Phone
________________________________
From: Thomas Narten
Sent: 10/3/2011 7:04 PM
To: [email-masked]
Subject: [nvo3] L2VPN overlap?
FYI, a discussion of sorts started on the L2VPN list as to whether L2
overlays as proposed for this list are already in-scope for the L2VPN
WG.

I.e., see http://www.ietf.org/mail-archive/web/l2vpn/current/msg02874.html

Thomas
_______________________________________________
nvo3 mailing list
[email-masked]
https://www.ietf.org/mailman/listinfo/nvo3