Subject: [Srcomp] The proposal text of Reference Scenarios of the analysis draft from Darren

From: "Weiqiang Cheng" <[email-masked]>
Date: Wed, 24 Feb 2021 20:43:14 +0800

Hi Team,

As we discussed before, we can begin to review the proposal text of
Reference Scenarios of the analysis draft from Darren.

Hope we can get closure soon and add the scenarios to the revision-01 when
the submission window is open.

2.1. Encapsulation Header Size

The compression proposal MUST reduce the size of the SRv6 encapsulation
header.

Encapsulation header size is evaluated against multiple reference scenarios.

2.1.1. Reference Scenario 1

A service provider offers a VPN service with underlay optimization in the SR
domain.

·         Hosts H1 and H2 are located in two different sites of a VPN
customer.

·         Edge nodes E3 and E4 encapsulate/decapsulate traffic between H1
and H2 to provide the VPN service.

·         A VPN SID is added to the encapsulation between E3 and E4.

·         An SR policy is applied consisting of 2 transport SIDs per domain.

·         The resulting segment list is described as 3D(2T).V (3 domains, 2
transport SIDs per domain, one VPN SID)

o    It contains at least 7 SIDs,

o    some proposals may require more SIDs be added to:

§  traverse domains

§  reach the egress node

·         This reference scenario is considered for different sub-domain
sizes (i.e. number of routers in the sub-domain)

o    Proposals offering 16 or 32-bit segment sizes are evaluated.

o    A 48-bit SRv6 block size is used.

This scenario results in E and ES for 16-bit and 32-bit variants of each
proposal.

16-bit SIDs

CSID

CRH

VSID

UIDSR

E(3D(2T).V)

64 octets

64 octets

72 octets

ES(3D(2T).V)

55.6%

55.6%

50%

32-bit SIDs

CSID

CRH

VSID

UIDSR

E(3D.2T.V)

80 octets

80 octets

80 octets

ES(3D.2T.V)

44.4%

44.4%

44.4%

Conclusion: In this scenario CSID and CRH performs better than other
proposals

2.1.2. Reference Scenario Set 1-30

Twenty nine additional scenarios are generated using the same parameters as
scenario 1 (D,T,V) by:

·         Varying the number of sub-domains in which traffic engineering is
required (1 to 3).

·         Varying the number of transport SID per sub-domain (0 to 15), such
that a scenario's segment list does not exceeding 16 SIDs (including the VPN
SID).

This results in a total of thirty segment lists, six for 3D(0..5T).V, eight
for 2D(0..7T).V, and sixteen for 1D(0..15T).V

The average encapsulation savings across all scenarios, for 16-bit and
32-bit variants of each proposal is documented in the following tables.

16-bit SIDs

CSID

CRH

VSID

UIDSR

Average ES

51.3%

49.7%

45.9%

32-bit SIDs

CSID

CRH

VSID

UIDSR

Average ES

40.1%

39.4%

42.7%

Conclusion: In this scenario set, CSID and VSID perform better than other
proposals.