Re: [arp222] ARP222 Charter statement and milestones

Benson Schliesser <> Thu, 26 August 2010 20:11 UTC

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From: Benson Schliesser <>
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Date: Thu, 26 Aug 2010 15:11:50 -0500
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To: Linda Dunbar <>,
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Subject: Re: [arp222] ARP222 Charter statement and milestones
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Linda -

I'd like to see a few modifications to the charter you've outlined:

1) I've already explained why I think the last design goal (overlapping IP addresses within a single VLAN) should be removed.  I won't reiterate that here.

2) The goal to "not break DHCP" should be modified to include any broadcast and/or multicast protocols.  (Alternatively, broadcast and multicast support can be required by a new goal to be added.)

3) The goal of supporting interconnect scenarios should explicitly include L3VPN.  In case it isn't clear, that implies a goal of support for overlapping IP addresses within the datacenter. (Albeit in different broadcast domains, my comments in #1 above notwithstanding.)

4) A new goal should include a performance analysis of all solutions considered.  This might explicitly acknowledge a role for negative caching approaches, but that shouldn't be a requirement.


On 12 Aug 10, at 6:14 PM, Linda Dunbar wrote:

> Thank you all for coming to ARP222 Bar BOF at the 78th IETF and giving us comments and suggestions on and between sessions.
> I put together the initial ARP222 Charter Statement and Milestones. Please provide comments and suggestions.  
> ARP 222: Address Resolution Protocol for Layer 2 to Anything to Layer 2
> Description of Working Group:
> As server virtualization is introduced to data centers, the number of hosts in a data center can grow dramatically because each physical server, which used to host one end-station, now can host many end-stations, or Virtual Machines (20, 30, or hundreds of). Virtual Machines, with its flexible add/delete and mobility features, not only makes it possible for achieving better performance and better utilization on servers, they are also a very important building block for Cloud Computing service to offer virtual subnets and virtual hosts. The virtual subnets offered by Cloud Computing service could allow clients to define their own subnets with its own IP addresses and policies.
> This rapid growth of virtual hosts could tremendously impact to networks and servers. One huge issue is frequent address resolution (IPv4) or neighbor discovery (IPv6) requests from hosts. All hosts frequently send out those requests due to their cache being aged out in minutes. With tens of thousands of hosts (each with a distinct MAC address) in one Data Center, the amount of address resolution packets per second is potentially more than 1,000 to 10,000/second. This rate imposes tremendous computational burden on many hosts.
> Another big issue associated with huge number of virtual hosts in a data center is potentially duplicated IP addresses within one VLAN which will make traditional ARP or ND not working properly. Some load balance design requires multiple hosts serving the same application to have the same IP address but with different MAC addresses. Cloud Computing service could allow users to have their own subnets with IP addresses and self defined policies among those subnets. Some network designs need to put multiple client subnets into one VLAN because the number of client subnets could be in hundreds of thousands which is much more than 4095 VLANs. Under this scenario, there could be duplicated IP addresses which are from different client subnets ending up in one VLAN. 
> The goal of this working group is to develop interoperable solutions to solve those problems. 
> The design should consider the following properties:
> All solutions developed by ARP222 WG should not expect any behavior changes on hosts, applications, or Virtual Machines being deployed in the market.
> All solutions developed should not break DHCP.
> Evaluating the impact to IPv6 ND, and develop solutions accordingly if needed.
> Should consider variety of solutions, including directory based, proxy based, or cache based solutions.
> Include analysis of security concerns of IPv4 ARP requests from malicious users. Evaluating potential security solutions and conclude if the security threat can justify solutions.
> ARP222 assumes the direct links to individual hosts and virtual machines are IEEE802.3 Ethernet links. 
> Should consider scenarios of one Ethernet network being interconnected by another network, which can be L2VPN, pure IP, Ethernet, or others.
> Should consider address resolution solutions for one VLAN with small number of duplicated IP addresses.  
> Here are the items which should not be in the scope of the working group:
> Re-define DHCP behavior
> Re-define security concern to IPv6 ND
> Direct links from hosts and virtual hosts are non Ethernet links
> Goals and Milestones:
> Charter statement
> Problem Statements
> Gap analysis
> Study of NHRP (RFC2332) & SCSP,  and their applicability to Ethernet networks
> Study and Analysis of MOOSE as a potential solution
> Study and Analysis of SEATTLE as a potential solution.
> Best Regards, Linda Dunbar
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