Internet DRAFT - draft-xxx-spring-sr-enhanced-detnet
draft-xxx-spring-sr-enhanced-detnet
Network Working Group X. Geng
Internet-Draft Z. Li
Intended status: Standards Track T. Zhou
Expires: 12 January 2023 Huawei
11 July 2022
Segment Routing for Enhanced DetNet
draft-xxx-spring-sr-enhanced-detnet-00
Abstract
One of the goals of DetNet is to provide bounded end-to-end latency
for critical flows. This document defines how to leverage Segment
Routing(SR) and Segment Routing over IPv6 (SRv6) to implement bounded
latency. Specifically, new SRv6 SID function is used to specify
bounded latency information for a packet. When forwarding devices
along the path follow the instructions carried in the packet, the
bounded latency is achieved by different implementations based on
bounded latency information.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 12 January 2023.
Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology and Conventions . . . . . . . . . . . . . . . . . 3
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Conventions . . . . . . . . . . . . . . . . . . . . . . . 3
3. SRv6 for Enhanced DetNet . . . . . . . . . . . . . . . . . . 4
3.1. End.X.BL: Forwarding the packet with bounded latency
guarantee . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2. End.X.BLI: Forward the packet with bounded latency
guarantee though BLI . . . . . . . . . . . . . . . . . . 7
3.2.1. BLI in Arguments of End.X.BLI SID . . . . . . . . . . 8
3.2.2. BLI in TLV of SRH . . . . . . . . . . . . . . . . . . 9
4. SR MPLS for Enhanced DetNet . . . . . . . . . . . . . . . . . 13
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
6. Security Considerations . . . . . . . . . . . . . . . . . . . 14
7. Normative References . . . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction
Deterministic Networking(DetNet) provides a capability to carry
specified data flows with extremely low data loss rates and bounded
latency within a network domain. DetNet is enabled by a group of
technologies, such as resource allocation, service protection and
explicit routes ([RFC8655]).
Segment Routing(SR) leverages the source routing paradigm. A ingress
node steers a packet through an ordered list of instructions, called
"segments". When SR is used over the MPLS data plane, SIDs are an
MPLS label or an index into an MPLS label space (either SRGB or
SRLB).
SR can also be applied over IPv6 data plane using Routing Extension
Header(SRH). Besides routing, the segment of SRv6 can indicate
functions which are executed locally in the node where they are
defined. SRv6 network programming makes it convenient to add
sophisticated operations in the network. ([RFC8402])
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DetNet data plane is enhanced to facilitate DetNet transit nodes to
support end-to-end bounded latency transmission.
[I-D.yzz-detnet-enhanced-data-plane] introduces an unified data plane
feild for bounded latency, which is called Bounded Latency
Information(BLI) BLIis designed to cope with a variety of
queuing/scheduling/shaping mechanisms in a uniform format in the data
plane.
This document describes how to implement DetNet with SR or SRv6. It
can provide : 1. Source routing, which can steer the DetNet flows go
through the network according to an explicit route with allocated
resource by segment list in SRH; 2. Network programming, which can
give packet instructions in every node along the path to guarantee
bounded latency. DetNet SR MPLS/SRv6 data plane extensions for
enhanced DetNet are defined in this document.
2. Terminology and Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
2.1. Terminology
Terminologies for DetNet go along with the definition in [RFC8655].
Other terminologies are defined as follows:
* NH: The IPv6 next-header field.
* SID: A Segment Identifier which represents a specific segment in a
segment routing domain([RFC8402]).
* SRH: The Segment Routing Header ([RFC8754]).
2.2. Conventions
Conventions in the document are defined as follows:
* NH=SRH means that NH is 43 with routing type 4.
* A SID list is represented as <S1, S2, S3> where S1 is the first
SID to visit, S2 is the second SID to visit and S3 is the last SID
to visit along the SR path.
* SRH[SL] represents the SID pointed by the SL field, that is the
SLth SID in the Segment List.
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* (SA,DA) (S3, S2, S1; SL) represents an IPv6 packet with:
IPv6 header with source and destination addresses SA and DA
respectively, and next-header SRH, with SID list <S1, S2, S3>
with SegmentsLeft = SL
The payload of the packet is not represented
(S3, S2, S1; SL) represents the same SID list as <S1, S2, S3>,
but encoded in the SRH format where the rightmost SID in the
SRH is the first SID and the leftmost SID in the SRH is the
last SID
3. SRv6 for Enhanced DetNet
To guarantee the end-to-end bounded latency transmission in DetNet
network, bounded latency information is required to be conveyed
inband with the service data to facilitate the queuing algorithm
performed on the DetNet transit nodes. When the bounded latency
information is used in DetNet IP data plane or DetNet MPLS data
plane, it is carried in IP/UDP or MPLS encapsulations. When the
bounded latency information is used in TSN over IP/MPLS data plane,
the information used in TSN networks is transparently transmitted IP/
UDP or MPLS encapsulations. Note that, which queuing mechanism is
used is a local choice determined by DetNet transit nodes. It is not
necessary to be explicitly indicated in packets.
When an SRv6 SID is in the Destination Address field of an IPv6
header of a packet, it is routed through transit nodes in an IPv6
network as an IPv6 address. SRv6 SID consists of LOC:FUNCT:ARG,
where a locator (LOC) is encoded in the L most significant bits of
the SID, followed by F bits of function (FUNCT) and A bits of
arguments (ARG), which is defined in ([RFC8986]).
Bounded Latency Information (BLI) is defined in
[I-D.yzz-detnet-enhanced-data-plane] to guide forwarding in network
device, which could be initiated in SRv6 data plane. With the
characteristics of Segment Routing, the bounded latency information
could be coupled with explicit path to provide latency guarantee in
each node/ adjacency indicated by the segment list.
Bounded Latency Information is indicated by the allocated SID at each
node along the path without maintaining per-flow states at the
intermediate and egress nodes. Hence, it naturally supports flow
aggregation, and that allows DetNet to support large number of DetNet
flows and scale to large networks.
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As defined in [I-D.yzz-detnet-enhanced-data-plane], 8 or more Bounded
Latency Information Types (BLI Type) are introduced to differentiate
the types of BLIs, based on the required information of
queuing/scheduling/shaping mechanisms to guarantee bounded latency.
Bounded Latency Information Value (BLI Value) is a specified value of
a specific type of BLI to provide guidance for packet processing with
the meaning of a particular BLI type. The pair <BLI Type, BLI Value>
information should be indicated by SRv6 data plane.
The "Endpoint with L3 cross-connect" behavior ("End.X" for short) is
a variant of the End behavior. It is the SRv6 instantiation of an
Adj-SID ([RFC8402]), and its main use is for traffic-engineering
policies.
Two new variations of End.X SID are defined for DetNet bounded
latency, which are called End.X.BL and End.X.BLI respectively, and
bounded latency information can be defined as functions or arguments
in the new types of SID.
Editors Notes: Another option to implement this is to define new
flavors. This method will be considered when not only End.X could be
combined with BLI.
3.1. End.X.BL: Forwarding the packet with bounded latency guarantee
This document defines End.X.BL, which is used to identify Bounded
Latency Information for Enhanced DetNet. End.X.BL a variation of
End.X.
End.X.BL SID has two meanings: 1) to identify an interface/link, just
like the adjacency SID; 2) to identify the pair <BLI Type and BLI
Value> information on the interface/link to guarantee bounded
latency. So different End.X.BL SIDs could be allocated to the same
interface/link in order to indicated different pairs <BLI Type, BLI
Value>.
The SRv6 encapsulation with End.X.BL SIDs is shown as follows:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Next Header | Hdr Ext Len | Routing Type | Segment Left |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Last Entry | Flags | Tag |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Segment List[0] |
| which is End.X.BL SID |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Segment List[n] |
| which is End.X.BL SID |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Optional TLVS |
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
When N receives a packet destined to S and S is a local End.X.BL SID,
N does the following:
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S01. When an SRH is processed {
S02. If (Segments Left == 0) {
S03. Stop processing the SRH, and proceed to process the next
header in the packet, whose type is identified by
the Next Header field in the routing header.
S04. }
S05. If (IPv6 Hop Limit <= 1) {
S06. Send an ICMP Time Exceeded message to the Source Address
with Code 0 (Hop limit exceeded in transit),
interrupt packet processing, and discard the packet.
S07. }
S08. max_LE = (Hdr Ext Len / 2) - 1
S09. If ((Last Entry > max_LE) or (Segments Left > Last Entry+1)) {
S10. Send an ICMP Parameter Problem to the Source Address
with Code 0 (Erroneous header field encountered)
and Pointer set to the Segments Left field,
interrupt packet processing, and discard the packet.
S11. }
S12. Decrement IPv6 Hop Limit by 1
S13. Decrement Segments Left by 1
S14. Update IPv6 DA with Segment List[Segments Left]
S15. Submit the packet to the IPv6 module for transmission
to the new destination via a L3 adjacency indicated by the
End.X.BL SID
S16. Send the packet out using <BLI Type, BLI Value> indicated by the
End.X.BL SID with the corresponding bounded latency guarantee
mechanism
S17. }
3.2. End.X.BLI: Forward the packet with bounded latency guarantee
though BLI
The "Endpoint with forwarding the packet with bounded latency
guarantee by BLI" behavior ("End.X.BLI" for short) is a variant of
the End behavior.
End.X.BLI SID has two meanings: 1) to identify an interface/link,
just like the adjacency SID; 2)to identify the BLI Type to guarantee
bounded latency. So different End.X.BLI could be allocated to the
same interface/link in order to indicated different types of BLIs.
The BLI Value corresponding to the End.X.BLI SID is carried
explicitly in the SRv6 packet header.
There are 3 possible options for carrying variable BLI Value
associated with the End.X.BLI SID, including:
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* Option1: Arguments in End.X.BLI SID
* Option2: SRH TLV for BLI used together with End.X.BLI SID
* Option3: New options in DoH before SRH together with End.X.BLI SID
3.2.1. BLI in Arguments of End.X.BLI SID
The behavior also takes an argument: "Arg.BLI". This argument
provides a local BLI Value information for bounded latency guarantee.
The SRH with End.X.BLI SIDs is showed as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Next Header | Hdr Ext Len | Routing Type | Segment Left |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Last Entry | Flags | Tag |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+---
| Location & Function |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+End.X.BLI
| Bounded Latency Information |SID
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+---
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Segment List[n] |
| which is End.X.BLI SID |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Optional TLVS |
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where
* Location&Function: the most significant bits that are used for
routing and function indication;
* Bounded Latency Information : the least significant bits, which is
defined [I-D.yzz-detnet-enhanced-data-plane].
When N receives a packet destined to S and S is a local End.X.BLI
SID, N does the following:
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S01. When an SRH is processed {
S02. If (Segments Left == 0) {
S03. Stop processing the SRH, and proceed to process the next
header in the packet, whose type is identified by
the Next Header field in the routing header.
S04. }
S05. If (IPv6 Hop Limit <= 1) {
S06. Send an ICMP Time Exceeded message to the Source Address
with Code 0 (Hop limit exceeded in transit),
interrupt packet processing, and discard the packet.
S07. }
S08. max_LE = (Hdr Ext Len / 2) - 1
S09. If ((Last Entry > max_LE) or (Segments Left > Last Entry+1)) {
S10. Send an ICMP Parameter Problem to the Source Address
with Code 0 (Erroneous header field encountered)
and Pointer set to the Segments Left field,
interrupt packet processing, and discard the packet.
S11. }
S12. Decrement IPv6 Hop Limit by 1
S13. Decrement Segments Left by 1
S14. Update IPv6 DA with Segment List[Segments Left]
S15. Submit the packet to the IPv6 module for transmission
to the new destination via a L3 adjacency indicated by the
End.X.BLI SID
S16. Send the packet out using BLI Type indicated by the
End.X.BLI SID and BLI Value carried in the argument
with the corresponding bounded latency guarantee mechanism
S17. }
3.2.2. BLI in TLV of SRH
Optional TLV defined in SRH could also be extended for BLI, which is
used together with End.X.BLI.
3.2.2.1. BLI List TLV
When all or part of the nodes/adjacencies in the explicit path
indicated by the segment list request different BLI values
corresponding to the End.X.BLI SID to guarantee bounded latency, a
BLI List TLV is defined. The SRH with End.X.BLI SIDs is showed as
follows:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Next Header | Hdr Ext Len | Routing Type | Segment Left |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Last Entry | Flags | Tag |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Segment List[n] |
| which is End.X.BLI SID |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Segment List[1] |
| which is End.X.BLI SID |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type(TBD1) | Length | BLI Left | RESERVED |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BLI List [m] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BLI List [1] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Type field is 8 bits in length, and the value is TBD1.
The Length field is 8 bits in length and its value is variable, which
depends on the length of BLI list.
BLI Left: 8-bit unsigned integer. Number of BLI remaining, i.e.,
number of explicitly listed intermediate nodes still to be visited
before reaching the final destination.
BLI List[0..m]: 32-bit unsigned integer, representing the nth BLI in
the BLI list.
The BLI in the BLI list corresponds to the Segment in the Segment
List one by one. The length of BLI List depends on the number of
End.X.BLI in the segment list.
When N receives a packet destined to S and S is a local End.X.BLI
SID, N does the following:
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S01. When an SRH is processed {
S02. If (Segments Left == 0) {
S03. Stop processing the SRH, and proceed to process the next
header in the packet, whose type is identified by
the Next Header field in the routing header.
S04. }
S05. If (IPv6 Hop Limit <= 1) {
S06. Send an ICMP Time Exceeded message to the Source Address
with Code 0 (Hop limit exceeded in transit),
interrupt packet processing, and discard the packet.
S07. }
S08. max_LE = (Hdr Ext Len / 2) - 1
S09. If ((Last Entry > max_LE) or (Segments Left > Last Entry+1)) {
S10. Send an ICMP Parameter Problem to the Source Address
with Code 0 (Erroneous header field encountered)
and Pointer set to the Segments Left field,
interrupt packet processing, and discard the packet.
S11. }
S12. Decrement IPv6 Hop Limit by 1
S13. Decrement Segments Left by 1
S14. Update IPv6 DA with Segment List[Segments Left]
S15. Submit the packet to the IPv6 module for transmission
to the new destination via a L3 adjacency
S16. Send the packet out using BLI Type indicated by the
End.X.BLI SID and BLI Value carried by BLI List[BLI Left]
in SRH TLV and BLI Left--
with the corresponding bounded latency guarantee mechanism
S17. }
3.2.2.2. Shared BLI TLV
When all the nodes/adjacencies in the explicit path indicated by the
segment list request the same BLI value to guarantee bounded latency,
the Shared BLI TLV is defined. The SRH with End.X.BLI SIDs is showed
as follows:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Next Header | Hdr Ext Len | Routing Type | Segment Left |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Last Entry | Flags | Tag |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Segment List[n] |
| which is End.X.BLI SID |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Segment List[1] |
| which is End.X.BLI SID |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type(TBD2) | Length | RESERVED |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Shared BLI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Type field is 8 bits in length, and the value is TBD2.
The Length field is 8 bits in length and its value is variable, which
depends on the length of BLI list.
The Shared BLI field is 32 bits in length and corresponds to
definition of BLI in [I-D.yzz-detnet-enhanced-data-plane].
When N receives a packet destined to S and S is a local End.X.BLI
SID, N does the following:
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S01. When an SRH is processed {
S02. If (Segments Left == 0) {
S03. Stop processing the SRH, and proceed to process the next
header in the packet, whose type is identified by
the Next Header field in the routing header.
S04. }
S05. If (IPv6 Hop Limit <= 1) {
S06. Send an ICMP Time Exceeded message to the Source Address
with Code 0 (Hop limit exceeded in transit),
interrupt packet processing, and discard the packet.
S07. }
S08. max_LE = (Hdr Ext Len / 2) - 1
S09. If ((Last Entry > max_LE) or (Segments Left > Last Entry+1)) {
S10. Send an ICMP Parameter Problem to the Source Address
with Code 0 (Erroneous header field encountered)
and Pointer set to the Segments Left field,
interrupt packet processing, and discard the packet.
S11. }
S12. Decrement IPv6 Hop Limit by 1
S13. Decrement Segments Left by 1
S14. Update IPv6 DA with Segment List[Segments Left]
S15. Submit the packet to the IPv6 module for transmission
to the new destination via a L3 adjacency
S16. Send the packet out using BLI Type indicated by the
End.X.BLI SID and BLI Value indicated by Shared BLI TLV
with the corresponding bounded latency guarantee mechanism
S17. }
3.2.2.3. BLI Options in DOH before SRH
According to [RFC8200], BLI could also be defined through DOH before
SRH for the specified segment. For the case of BLI List, considering
that the location of DOH is before SRH, it is not recommended to be
defined in DoH, because it will affect the processing efficiency of
Segment in SRH. For Shared BLI TLV, it can be carried by the DOH
Option. In order for the consistency, this document recommends to
use the SRH TLV to carry both information.
4. SR MPLS for Enhanced DetNet
For SR MPLS data plane, this document defines a new segment that is
called a BLI Segment, which is used to identify Bounded Latency
Information for Enhanced DetNet just like End.BL SID. A BLI Segment
is an adjacency segment and allocated from the Segment Routing Local
Block (SRLB)[RFC8402]. BLI Segment indicateds <BLI Type, BLI Value>
of an interface/link. So different BLI segments could be allocated
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to the same interface/link in order to indicated different pairs <BLI
Type, BLI Value>.
Editors Notes: SR MPLS extension with meta data which is still under
discussion will be defined based on the progress of MPLS DT. The
possible definition of MPLS segment associated with the variable BLI
values like the SRv6 End.X.BLI will be defined in the future version.
5. IANA Considerations
The following codepoints are defined in this document in Segment
Routing Header TLVs registry:
+---------+--------------------------+---------------+
| Value | Description | Reference |
+=========+==========================+===============+
| TBD1 | BLI List TLV | This document |
+---------+--------------------------+---------------+
| TBD2 | Shared BLI TLV | This document |
+---------+--------------------------+---------------+
6. Security Considerations
TBD
7. Normative References
[I-D.ietf-detnet-bounded-latency]
Finn, N., Boudec, J. L., Mohammadpour, E., Zhang, J., and
B. Varga, "DetNet Bounded Latency", Work in Progress,
Internet-Draft, draft-ietf-detnet-bounded-latency-10, 8
April 2022, <https://www.ietf.org/archive/id/draft-ietf-
detnet-bounded-latency-10.txt>.
[I-D.yzz-detnet-enhanced-data-plane]
Yang, F., Zhou, T., and L. Zhang, "DetNet Enhanced Data
Plane", Work in Progress, Internet-Draft, draft-yzz-
detnet-enhanced-data-plane-00, 10 July 2022,
<https://www.ietf.org/archive/id/draft-yzz-detnet-
enhanced-data-plane-00.txt>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
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[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>.
[RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas,
"Deterministic Networking Architecture", RFC 8655,
DOI 10.17487/RFC8655, October 2019,
<https://www.rfc-editor.org/info/rfc8655>.
[RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J.,
Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
(SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020,
<https://www.rfc-editor.org/info/rfc8754>.
[RFC8986] Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer,
D., Matsushima, S., and Z. Li, "Segment Routing over IPv6
(SRv6) Network Programming", RFC 8986,
DOI 10.17487/RFC8986, February 2021,
<https://www.rfc-editor.org/info/rfc8986>.
Authors' Addresses
Xuesong Geng
Huawei
Email: gengxuesong@huawei.com
Zhenbin Li
Huawei
Email: lizhenbin@huawei.com
Tianran Zhou
Huawei
Email: zhoutianran@huawei.com
Geng, et al. Expires 12 January 2023 [Page 15]
