Practices for scaling ARP and ND for large data centers
draft-dunbar-armd-arp-nd-scaling-practices-04

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ARMD                                                L. Dunbar
Internet Draft                                         Huawei
Intended status: Informational                     W. Kumari
Expires: June 2013                                    Google
                                              Igor Gashinsky
                                                       Yahoo
                                            December 11, 2012

      Practices for scaling ARP and ND for large data centers

           draft-dunbar-armd-arp-nd-scaling-practices-04

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                       Expires June 11, 2013                 [Page 1]
Internet-Draft   Pratices to scale ARP/ND in large DC

Abstract

   This draft documents some simple practices that scale ARP/ND
   in data center environments.

Table of Contents

   1. Introduction ................................................ 3
   2. Terminology ................................................. 3
   3. Common DC network Designs.................................... 4
   4. Layer 3 to Access Switches................................... 4
   5. Layer 2 practices to scale ARP/ND............................ 5
      5.1. Practices to alleviate APR/ND burden on L2/L3
      boundary routers ............................................ 5
         5.1.1. Station communicating with an external peer........ 5
         5.1.2. L2/L3 boundary router processing of inbound
         traffic .................................................. 6
         5.1.3. Inter subnets communications ...................... 7
      5.2. Static ARP/ND entries on switches ....................... 7
      5.3. ARP/ND Proxy approaches ................................. 8
   6. Practices to scale ARP/ND in Overlay models .................. 8
   7. Summary and Recommendations .................................. 9
   8. Security Considerations ...................................... 9
   9. IANA Considerations ......................................... 9
   10. Acknowledgements .......................................... 10
   11. References ................................................ 10
      11.1. Normative References.................................. 10
      11.2. Informative References................................ 10
   Authors' Addresses ............................................ 11

Dunbar-Kumari-Gashinsky    Expires June 11, 2013  [Page 2]
Internet-Draft   Pratices to scale ARP/ND in large DC

1. Introduction

   As described in [ARMD-Problem], the increasing trend of
   rapid workload shifting and server virtualization in modern
   data centers requires servers to be loaded (or re-loaded)
   with different VMs or applications at different times.
   Different VMs residing on one physical server may have
   different IP addresses, or may even be in different IP
   subnets.

   In order to allow a physical server to be loaded with VMs in
   different subnets, or VMs to be moved to different server
   racks without IP address re-configuration, the corresponding
   networks need to enable multiple broadcast domains (many
   VLANs) on the interfaces of L2/L3 boundary routers and ToR
   switches. Unfortunately, when the combined number of VMs (or
   hosts) in all those subnets is large, this can lead to
   address resolution scaling issues, especially on the L2/L3
   boundary routers.

   This draft documents some simple practices which can scale
   ARP/ND in data center environment.

2. Terminology

   This document reuses much of terminology from [ARMD-