Network Working Group L. Gong
Internet Draft China Mobile
Intended status: Standards Track C. Lin
Expires: October 10, 2024 New H3C Technologies
April 10, 2024
SRv6 Resource Programming with NRP flavor
draft-gong-spring-srv6-nrp-flavor-00
Abstract
This document introduces a new flavor type for SRv6 called "Flavor
NRP". It associates the SRv6 End.X SID with a set of network
resource partitions (referred to as NRP resources). By using the
End.X SID with the NRP flavor type, SRv6 policies can provide
programmability for network resources.
Status of this Memo
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This Internet-Draft will expire on October 10, 2024.
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Table of Contents
1. Introduction...................................................3
1.1. Requirements Language.....................................3
2. NRP Flavor.....................................................3
3. Use Cases for NRP Flavor.......................................4
4. Security Considerations........................................5
5. IANA Considerations............................................5
6. References.....................................................6
6.1. Normative References......................................6
Authors' Addresses................................................7
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1. Introduction
The concept of network resource partition (NRP) is introduced in [I-
D.ietf-teas-ietf-network-slices]. NRP is a set of network resources
allocated from the underlying network, which is used to carry
specific network traffic and meet the desired Service Level
Objectives (SLOs) and Service Level Expectations (SLEs).
Segment Routing (SR) [RFC8402] guides packets using an ordered list
of instructions called "segments". Each instruction represents a
function performed at a specific location in the network. This
function is locally defined on the executing node and can range from
simple forwarding to complex user-defined behaviors. Network
programming combines the functions of Segment Routing, which are
both simple and complex, to achieve network objectives beyond simple
packet routing.
When the SRv6 network provides network slicing services, the SRv6
Endpoint behaviors defined in [RFC8986] are not associated with
slice-specific network resources (e.g., regular End.X simply
forwards packets to endpoints with 'layer-3 adjacency'). Therefore,
there is a lack of orchestration for network resources, including
link bandwidth, buffer, and queues.
This document defines a new flavor type for SRv6 called "NRP Flavor
" which allows the SID to be associated with a set of network
resource partitions (e.g., bandwidth, buffer, and queue resources).
By programming the SRv6 policy path using SIDs with the NRP flavor
type, programmability for SRv6 network resources is achieved.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. NRP Flavor
This section defines a new SRv6 Endpoint behavior that can be used
to associate with a set of network resource partitions (such as
bandwidth, buffer, and queue resources) and identified by the End.X
SID with the Flavor type NRP.
The behavior of selecting NRP resources can be identified and chosen
using the End.X with Flavor type NRP [RFC8986]. When a packet
destined to S is received by N and S is a local End.X with Flavor
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type NRP, the Step 15 in the End.X processing defined in [RFC8986]
is replaced with the following:
Any instance of End.X SID with Flavor NRP behavior is associated not
only with one or more L3 adjacencies or L2 Bundles but also with the
corresponding NRP resources.
S15. Submit the packet to the IPv6 module for transmission to the
new destination via a member of J. If the Flavor type is NRP,
use the NRP resources (such as bandwidth, buffer, and queue
resources) associated with this SID for packet forwarding.
These End.X SIDs with Flavor type NRP can be assigned by a
centralized network controller or network nodes, and can be
advertised using IGP or BGP-LS, similar to the regular End.X SID
advertisement behavior.
3. Use Cases for NRP Flavor
This section outlines the possible flow of using End.X behavior with
Flavor NRP type.
A set of End.X SIDs with Flavor NRP type can be assigned for network
resource allocation related to SRv6 policies, to direct service
traffic towards different sets of link resources (e.g., bandwidth,
buffer, and queue resources) in packet forwarding. The association
of this group of End.X SIDs with network resource allocation is
identified by using Flavor NRP.
+-----+ +-----+ +-----+ +-----+
| R1 |------------| R2 |-------------| R3 |-------------| R4 |
+-----+ +-----+ +-----+ +-----+
End.X11(NRP) End.X12(NRP) End.X13(NRP)
BW:1G BW:1G BW:1G
NRP-ID 100 NRP-ID 100 NRP-ID 100
End.X21(NRP) End.X22(NRP) End.X23(NRP)
BW:2G BW:2G BW:2G
NRP-ID 200 NRP-ID 200 NRP-ID 200
Figure : usecase of Flavor NRP End.X
As shown in Figure 1, there are two network resource partitions:
NRP-ID 100 and NRP-ID 200, allocated for two network slices. The
End.X SIDs with Flavor type NRP can be associated with a group of
network resource partitions assigned to the slice/slice aggregation.
Therefore, this group of End.X SIDs with Flavor type NRP can be used
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to build SR policies, and transit nodes can direct traffic to the
set of network resources allocated for that slice.
Here is a possible flow:
The controller obtains the topology information and calculates SRv6
Policy 1 and SRv6 Policy 2 based on SLAs.
The controller collaborates with network nodes to perform resource
reservation and allocation of End.X SIDs with Flavor type NRP along
SRv6 Policy 1 and SRv6 Policy 2. Taking the interface R1-R2 of SRv6
node R1 along SRv6 Policy 1 as an example, End.X11 is associated
with NRP-ID 100, which is the network resource partition identifier
for QoS queue for BW 1G, and End.X21 is associated with NRP-ID 200,
which is the network resource partition identifier for QoS queue for
BW 2G.
The controller uses End.X11, End.X12, and End.X13 to build the SID
list for SRv6 Policy 1, and uses End.X21, End.X22, and End.X23 to
build the SID list for SRv6 Policy 2.
Then, the controller notifies the ingress nodes about the segment
lists of SRv6 Policy 1 and SRv6 Policy 2 through various means,
including BGP [I-D.ietf-idr-segment-routing-te-policy].
4. Security Considerations
TBD.
5. IANA Considerations
This document requests the new assignment of End.X with NRP type
from "The initial registrations" for the Flavor type NRP of End.X.
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+==========+===============+=====================+==============+
| Value | Hex | Endpoint Behavior | Reference |
+==========+===============+=====================+==============+
| TBD | TBD | End.X with NRP | This Document|
+----------+---------------+---------------------+--------------+
| TBD | TBD | End.X with PSP& NRP | This Document|
+----------+---------------+---------------------+--------------+
| TBD | TBD | End.X with | |
| | | USP&USD&NRP | This Document|
+----------+---------------+---------------------+--------------+
| TBD | TBD | End.X with | |
| | | PSP&USP&USD&NRP | This Document|
+----------+---------------+---------------------+--------------+
6. References
6.1. Normative References
[I-D.ietf-teas-ietf-network-slices] Farrel, A., "Framework for IETF
Network Slices", Work in Progress, Internet-Draft, draft-
ietf-teas-ietf-network-slices-12, 30 June 2022,
<https://www.ietf.org/archive/id/draft-ietf-teas-ietf-
network-slices-12.txt>.
[I-D.ietf-teas-enhanced-vpn] Dong, J., "A Framework for Enhanced
Virtual Private Network (VPN+) Services", draft-ietf-
teas-enhanced-vpn-10, 6 March 2022,
<https://www.ietf.org/archive/id/draft-ietf-teas-enhanced-
vpn-10.txt>.
[RFC9352] P. Psenak, Ed.," IS-IS Extensions to Support Segment
Routing over the IPv6 Data Plane ", February
2023,<https://datatracker.ietf.org/doc/rfc9352/>.
[RFC7770], A. Lindem, Ed., Ed., "Extensions to OSPF for Advertising
Optional Router Capabilities", February 2016,
<https://datatracker.ietf.org/doc/rfc7770/>
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Authors' Addresses
Liyan Gong
China Mobile
China
Email: gongliyan@chinamobile.com
Changwang Lin
New H3C Technologies
China
Email: linchangwang.04414@h3c.com
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