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SCALED SOURCE TUNNEL ENDPOINT ADDRESSING

IP.com Disclosure Number: IPCOM000244589D
Publication Date: 2015-Dec-23
Document File: 4 page(s) / 62K

Publishing Venue

The IP.com Prior Art Database

Related People

Rohit Puri: AUTHOR [+7]

Abstract

Using an auxiliary table in a data center switch, compression of addresses can be achieved and scalability obtained without increasing the size of expensive lookup tables. A prefix-based Internet Protocol (IP) address is stored in the lookup tables instead of the host route, and the auxiliary table is used to mask certain bits of the IP address. This solution increases the scalability of support of southbound hypervisors without adding to the cost of increasing the lookup table size in an application specific integrated circuit (ASIC) in a data center switch.

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SCALED SOURCE TUNNEL ENDPOINT ADDRESSING

AUTHORS:

Rohit Puri

Satyam Sinha

Tom Edsall

  Kevin Chu Ashutosh Agrawal Alessandro Fulli Ravikanth Nasika

CISCO SYSTEMS, INC.

ABSTRACT

    Using an auxiliary table in a data center switch, compression of addresses can be achieved and scalability obtained without increasing the size of expensive lookup tables. A prefix-based Internet Protocol (IP) address is stored in the lookup tables instead of the host route, and the auxiliary table is used to mask certain bits of the IP address. This solution increases the scalability of support of southbound hypervisors without adding to the cost of increasing the lookup table size in an application specific integrated circuit (ASIC) in a data center switch.

DETAILED DESCRIPTION

     Today in some data centers, southbound communication is supported for Virtual Extensible Local Area Network (VXLAN) hypervisors. Each such hypervisor link involves creation of the VXLAN tunnel and this needs special hardware processing from the data center switches, e.g., top of rack (TOR) switches. See Figure 1 below. The source address of the hypervisor is stored in the application specific integrated circuit (ASIC) tables in the switches for lookup and verification purposes. This source address is referred hereinafter to as Source Tunnel Endpoint Internet Protocol (Src_TEP IP) address.

Copyright 2015 Cisco Systems, Inc.

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Figure 1

    Hardware tables to do Src TEP lookup are at a premium and usually have a size in the range of a few thousand entries, typically 8K/16k. However, there is a need to support more VXLAN tunnels especially when connected to the Data Center Interconnect (DCI), which serves as a Layer 2 extension between remote data centers, or to the external networks. A solution is presented herein to scale to a greater number of Src TEPs and to support many more southbound tunnels without adding more entries to a SrcTEP table in a data center switch.

The Solution Generally

    To achieve greater scalability, an auxiliary table is defined to program the prefix based Src_TEP addresses in the SrcTEP table. The unique advantage this brings is that the Src_TEP entries can be reduced by several multiples if contiguous Src_TEP entries can be grouped into a single prefix IP. An auxiliary table lookup for a given Src_TEP entry can result in a hit which results in "m" bits to mask out for the lookup in the SrcTEP table. These masked-out bits achieve the compression in the SrcTEP table and hence the scalability. Masked-out bits are stored and carried in the ASIC pipeline so that any packets destined to this Src_TEP can be reconstructed. This same level of compression is achieved in the egress pipeline.

Copyright 2015 Cisco Systems, Inc.

TOR

SrcTEP1

SrcTEP2

SrcTEP3

SrcTEP(n)

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The Solution in More Detail

    Every Src_TEP IP address is first looked up in...