Internet DRAFT - draft-ct-isis-nspfid-for-sr-paths
draft-ct-isis-nspfid-for-sr-paths
LSR Working Group U. Chunduri, Ed.
Internet-Draft Huawei USA
Intended status: Standards Track J. Tantsura
Expires: September 24, 2018 Nuage Networks
Y. Qu
Huawei USA
March 23, 2018
Usage of Non Shortest Path Forwarding (NSPF) IDs in IS-IS
draft-ct-isis-nspfid-for-sr-paths-01
Abstract
This document specifies the advertisement of Non Shortest Path
Forwarding IDentifier (NSPF ID) TLV and the computation procedures
for the same in IS-IS protocol. NSPF ID allows to simplify the data
plane path description of data traffic in SR deployments. This helps
mitigate the MTU issues that are caused by additional SR overhead of
the packet and allows traffic statistics.
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 RFC2119 [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
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This Internet-Draft will expire on September 24, 2018.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Mitigation with MSD and RLD . . . . . . . . . . . . . . . 3
1.2. Issues with Increased SID Depth . . . . . . . . . . . . . 3
1.3. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . 5
2. Non Shortest Path Forwarding IDentifier TLV . . . . . . . . . 6
2.1. Flags . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2. NSPF-ID Fields . . . . . . . . . . . . . . . . . . . . . 8
2.3. NSP sub-TLVs . . . . . . . . . . . . . . . . . . . . . . 9
2.4. Non-NSP sub-TLVs . . . . . . . . . . . . . . . . . . . . 9
3. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 10
4. NSPF ID Data Plane aspects . . . . . . . . . . . . . . . . . 12
4.1. MPLS Data Plane . . . . . . . . . . . . . . . . . . . . . 12
4.2. SRv6 Data Plane . . . . . . . . . . . . . . . . . . . . . 12
5. NSP Traffic Accounting . . . . . . . . . . . . . . . . . . . 12
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
8. Security Considerations . . . . . . . . . . . . . . . . . . . 13
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
9.1. Normative References . . . . . . . . . . . . . . . . . . 13
9.2. Informative References . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction
In a network implementing source routing, packets may be transported
through the use of segment identifiers (SIDs), where a SID uniquely
identifies a segment as defined in [I-D.ietf-spring-segment-routing].
In SR-MPLS, a segment is encoded as a label and an ordered list of
segments is encoded as a stack of labels. In SRv6, a segment is
encoded as an IPv6 address, with a new type of IPv6 routing header
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called SRH. An ordered list of segments is encoded as an ordered
list of IPv6 addresses in SRH [I-D.ietf-6man-segment-routing-header].
The segment may include one or more nodes, unidirectional adjacencies
between two nodes or service instruction by a particular node in the
network. A Non Shortest Path (NSP) could be a Traffic Engineered
(TE) path or an explicitly provisioned FRR path or a service chained
path. NSP can be described using list of segments in SR. However,
this creates a problem of having a relatively large stack imposed on
the data packet. A path that is encoded with SIDs can be a loose or
strict path. In a strict path all the nodes/links on the path are
encoded as SIDs, with the expense of number of total SIDs in the
stack.
1.1. Mitigation with MSD and RLD
The number of SIDs in the stack a node can impose is referred as
Maximum SID Depth (MSD) capability
[I-D.ietf-isis-segment-routing-msd], which must be taken into
consideration when computing a path to transport a data packet in a
network implementing segment routing. [I-D.ietf-isis-mpls-elc]
defines Readable Label Depth (RLD) that is used by a head-end to
insert Entropy Label pair (ELI/EL) at appropriate depth, so it could
be read by transit nodes. There are situations where the source
routed path can be excessive as path represented by SR SIDs need to
describe all the nodes and ELI/EL based on the readability of the
nodes in that path.
While MSD (and RLD) capabilities advertisement help mitigate the
problem for a central entity to create the right source routed path
per application/operator requirements; actual depth is still limited
by the underlying hardware in the data path.
1.2. Issues with Increased SID Depth
Consider the following network where SR-MPLS data plane is in use and
with same SRGB (5000-6000) on all nodes i.e., A1 to A7 and B1 to B7
for illustration:
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SID:10 SID:20 SID:30 SID:40 SID:50 SID:300(Ax) SID:60 SID:70
A1-------A2-------A3-------A4-------A5===============A6----------A7
\ / \5 5/ \ SID:310(Ay) \ /
\ 10 10/ +-A10-+ \ \10 /10
\ / SID:100 \ \ /
SID:80 \A8-----A9/SID:90 \ 40 \ /
/ \ +---+ \ /
/10 B2x:125 \10 \ \/
B1--------B2============B3----B4--------B5-------B6----------B7
SID:110 SID:120 SID:130 SID:140 SID:150 SID:160 SID:170
Figure 1: SR-MPLS Network
Global ADJ SIDs are provisioned between A5 and A6 .All other SIDs
shown are nodal SID indices.
All metrics of the links are set to 1, other values as configured.
Shortest Path from A1 to A7: A2-A3-A4-A5-A6-A7
NSP1: From A1 to A7 - A2-A8-B2-B2x-A9-A10-Ax-A7; Pushed Label
Stack @A1: 5020:5080:5120:5125:5090:5100:5300:5070 (where B2x is a
local ADJ-SID and Ax is a global ADJ-SID)
In the above example NSP1 is represented with a combination of
Adjacency and Node SIDs with a stack of 8 labels each. However, this
value can be larger, if the use of entropy label is desired and based
on the RLD capabilities of each node and additional labels required
to insert ELI/EL at appropriate places. Though above network is
shown with SR-MPLS data plane, problem is similar if the network were
a SR-IPv6 network with all SIDs encoded as IPv6 SIDs in SRH.
In various SR deployments, the following issues may arise:
a. Not all nodes in the path can support MSD or RLD needed to
satisfy user/operator requirements, when the number of SIDs
increased to describe the source routed path. This problem gets
multiplied by four times in SRH compared to MPLS data plane
because of the SID size (16 bytes) in SRH.
b. Even if all nodes can support the required MSD or RLD, the bigger
label stack/depth can cause potential MTU/fragmentation issues.
c. In some deployments, it is also required reducing the overhead in
the network layer, especially for low packet size packets, where
the actual data can be way lesser than all encapsulations and SR
path overheads.
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Apart from the above some deployments need path accounting statistics
for path monitoring and traffic re-optimizations.
[I-D.hegde-spring-traffic-accounting-for-sr-paths] proposes a
solution, however this further increases the depth of SID stack. The
approach could be counter productive in the environments, where SID
depth is already causing deployment issues as listed above.
To mitigate the above issues, and also to facilitate forwarding plane
a mechanism to identify the SR path with a corresponding data plane
identifier for accounting of traffic for SR paths, this draft
proposes a new IS-IS TLV (Section 2) to advertise the NSPs with Non
Shortest Path Forwarding IDentifier (NSPF ID).
This draft lays out procedure for IS-IS nodes to how to use NSPF ID
TLV in Section 3. With corresponding data plane, Section 3
mechanism, reduces the SID stack in the data plane from 8 SIDs shown
in SR-PATH-1 and SR-PATH-2 with a single NSPF ID. This draft also
introduce source routed paths with NSPF ID types defined for native
IPv4 and IPv6 data planes as defined in Section 2.2.
1.3. Acronyms
EL - Entropy Label
ELI - Entropy Label Indicator
MPLS - Multi Protocol Label Switching
MSD - Maximum SID Depth
MTU - Maximum Transferrable Unit
NSP - Non Shortest Path
SID - Segment Identifier
SPF - Shortest Path First
SR - Segment Routing
SRH - Segment Routing Header
SR-MPLS - Segment Routing with MPLS data plane
SRv6 - Segment Routing with Ipv6 data plane with SRH
SRH - IPv6 Segment Routing Header
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TE - Traffic Engineering
2. Non Shortest Path Forwarding IDentifier TLV
This section describes the encoding of NSPF ID TLV. This TLV can be
seen as having 3 logical section viz., encoding od FEC Prefix,
encoding of NSPF-ID with description of ordered path with sub-TLVs
and a set of optional non-NSP sub-TLVs which can be used to describe
one or more parameters of the path. Multiple instances of this TLV
MAY be advertised in IS-IS LSPs with different NSPF-ID Type and with
corresponding path description sub-TLVS. The NSPF-ID TLV has Type
TBD (suggested value xxx), and has the following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved | Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MT-ID | Prefix Len | FEC Prefix |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// FEC Prefix (continued, variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NSPF-ID Type | NSPF-ID Len | NSPF-ID Flags | NSPF-ID Algo |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// NSPF-ID (continued, variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|No.of NSP-STs | NSP sub-TLVs (Variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|No.of Other-STs| Non-NSP sub-TLVs(variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: NSPF ID TLV Format
Type - TBD from IS-IS top level TLV registry.
Length - Total length of the value field in bytes (variable).
Reserved - 1 Octet reserved bits for future use. Reserved bits
MUST be reset on transmission and ignored on receive.
Flags - Flags for this TLV are described in Section 2.1.
MT-ID - is the multi-topology identifier defined in [RFC5120] with
4 most significant bits reset on transmission and ignored on
receive. The remaining 12-bit field contains the MT-ID.
Prefix Len - contains the length of the prefix in bits. Only the
most significant octets of the Prefix are encoded.
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FEC Prefix - represents the Forwarding Equivalence Class at the
tail-end of the advertised NSP. The "FEC Prefix" corresponds to a
routable prefix of the originating node and it MAY have one of the
[RFC7794] flags set (X-Flag/R-Flag/N-Flag). Value of this field
MUST be 4 octets for IPv4 "FEC Prefix". Value of this field MUST
be 16 octets for IPv6 "FEC Prefix". Encoding is similar to TLV
135 and TLV 236 or MT-Capable [RFC5120] IPv4 (TLV 235) and IPv6
Prefixes (TLV 237) respectively.
2.1. Flags
Flags: 1 octet field of NSPD ID TLV has following flags defined.
These flags mostly related to applicability of this TLV in an L1 area
or entire IS-IS domain:
NSPF ID Flags Format
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|S|D|A| Rsrvd |
+-+-+-+-+-+-+-+-+
S - If set, the NSPF ID TLV MUST be flooded across the entire
routing domain. If the S flag is not set, the NSPF ID TLV MUST
NOT be leaked between IS-IS levels. This bit MUST NOT be altered
during the TLV leaking
D - when the NSPF ID TLV is leaked from IS-IS level-2 to level-1,
the D bit MUST be set. Otherwise, this bit MUST be clear. NSPF
ID TLVs with the D bit set MUST NOT be leaked from level-1 to
level-2. This is to prevent TLV looping across levels.
A - The originator of the NSPF ID TLV MUST set the A bit in order
to signal that the prefixes and NSPF-IDs advertised in the NSPF ID
TLV are directly connected to their originators. If this bit is
not set, this allows any other node in the network advertise this
TLV on behalf of the originating node of the "FEC Prefix". If the
NSPF ID TLV is leaked to other areas/levels the A-flag MUST be
cleared.
Rsrvd - reserved bits for future use. Reserved bits MUST be reset
on transmission and ignored on receive.
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2.2. NSPF-ID Fields
This represents the actual data plane identifier in the packet and
could be of any data plane as defined in type field. Both "FEC
Prefix" and NSPF-ID MUST belong to a same node in the network.
1. NSPF-ID Type: This is a new registry (TBD IANA) for this TLV and
the defined types are as follows. Type: 1 - MPLS SID/Label Type:
2 Native IPv4 Address Type: 3 Native IPv6 Address Type 4: IPv6
SID in SRv6 with SRH
2. NSPF-ID Len: Length of the NSPF Identifier field in octets and
this depends on the NSPF-ID type. See NSPF-ID below for the
length of this field and other considerations.
3. NSPF-ID Flags: 1 Octet field for NSPF-ID flags. Some of the bits
could be NSPF-ID type specific and each new type MUST define the
flags applicable to the NSPF-ID type. For NSPF-ID Type 1, the
flags are same as Section 2.1 definition in
[I-D.ietf-isis-segment-routing-extensions]. For NSPF-ID Type 2,
3 and NSPF-ID Type 4 only 'R' flag is applicable. Undefined
flags for each NSPF-ID type MUST be considered as reserved.
Reserved flag bits in each NSPF-ID type specific flags MUST be
reset on transmission and ignored on receive.
4. NSPF-ID Algo: 1 octet value represents the SPF algorithm.
Algorithm registry is as defined in
[I-D.ietf-isis-segment-routing-extensions].
5. NSPF-ID: This is the NSP forwarding identifier that would be on
the data packet. The value of this field is variable and it
depends on the NSPF-ID Type. For Type 1, this is and MPLS SID/
Label. For Type 2 this is a 4 byte IPv4 address. For Type 3 and
Type 4, it is a 16 byte IPv6 address. For NSPF-ID Type 2, 3 or
4, if the NSPF-ID Len is set to 0, then FEC Prefix would also
become the NSPF-ID. In the case when NSPF-ID Len is 0 and NSPF-
ID Type is 2, then FEC Prefix length MUST be a 4 byte IPv4
address. Similarly, if NSPF-ID Type is 3 or 4 with NSPF-ID Len
is set to 0, then FEC Prefix MUST be of a 16 byte IPv6 Address.
For NSPF-ID Type 2, 3 or 4, if the NSPF-ID Len is set to non zero
value, then the NSPF-ID MUST not be advertised as a routable
prefix in TLV 135, TLV 235, TLV 236 and TLV 237, but that MUST
belog to the node where "FEC Prefix" is advertised.
6. No.of NSP-STs: Total number of the NSP sub-TLVs are defined with
this 1-octet field. The value MUST NOT be zero.
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2.3. NSP sub-TLVs
A new sub-TLV registry is created (TBD IANA) called NSP sub-TLVs.
These are used to describe the path in the form of set of contiguous
and ordered sub-TLVs, with first sub-TLV representing the top of the
stack or first segment. These set of ordered TLVs can have both
topological SIDs and non-topological SIDs (e.g., service segments).
Type 1: SID/Label sub-TLV as defined in
[I-D.ietf-isis-segment-routing-extensions]. Only Type is defined
and Length/Value fields are per Section 2.3 of the referenced
document.
Type 2: Prefix SID sub-TLV as defined in
[I-D.ietf-isis-segment-routing-extensions]. Only Type is defined
and Length/Value fields are per Section 2.1 of the referenced
document.
Type 3: Adjacency SID sub-TLV as defined in
[I-D.ietf-isis-segment-routing-extensions]. Only Type is defined
and Length/Value fields are per Section 2.2 of the referenced
document.
Type 4: Length 4 bytes, value is 4 bytes IPv4 address encoded
similar to IPv4 FEC Prefix described above.
Type 5: Length 16 bytes; value is 16 bytes IPv6 address encoded
similar to IPv6 FEC Prefix described above.
Type 6: SRv6 Node SID TLV as defined in
[I-D.bashandy-isis-srv6-extensions]. Only Type is defined and
Length/Value fields are per Section 4 of the referenced document.
Type 7: SRv6 Adjacency-SID sub-TLV as defined in
[I-D.bashandy-isis-srv6-extensions]. Only Type is defined and
Length/Value fields are per Section 6.1 of the referenced
document.
Type 8: SRv6 LAN Adjacency-SID sub-TLV as defined in
[I-D.bashandy-isis-srv6-extensions]. Only Type is defined and
Length/Value fields are per Section 6.2 of the referenced
document.
2.4. Non-NSP sub-TLVs
NSPF ID TLV also defines a new sub-TLV registry (TBD IANA) for
defining extensible set of sub-TLVs other than describing the path
sub-TLVs. Total number of the path sub-TLVs to describe the path are
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defined in 1-octet field "No.of Other-STs" just before the Non-NSP
sub-TLVs. This field serves as a demarcation for set of ordered NSP
sub-TLVs and Non-NSP sub-TLVs.
Type 1: Length 0 No value field. Specifies a counter to count
number of packets forwarded on this NSPF-ID.
Type 2: Length 0 No value field. Specifies a counter to count
number of bytes forwarded on this NSPF-ID specified in the network
header (e.g. IPv4, IPv6).
Type 3: Length 4 bytes, and Value is metric of this path
represented through the NSPF-ID. Different nodes can advertise
the same NSPF-ID for the same FEC-Prefix with a different set of
NSP sub-TLVs and the receiving node MUST consider the lowest
metric value (TBD more, what happens when metric is same for two
different set of NSP sub-TLVs).
3. Elements of Procedure
As specified in Section 1, a NSP can be a TE path, locally
provisioned by the operator. Consider the following IS-IS network to
describe the operation of NSPF ID TLV as defined in Section 2:
1
_______
/ 1 \
+---R2-------R3---+
/ \_______/ \
/ 1 \
1 / 2 \ 1
/ ______ \
/ / \ \
R1------R6 R7-----------R4
\ 2 \______/ 2 /\
\ 2 / \
3 \ / 3 \1
\ 4 / \
+----R8------R9-----R10------R12
\ 1 /
1 \ / 1
+----R11---+
Figure 3: IS-IS Network
In the above diagram (Figure 3) node R1 is an ingress node, or a
head-end node, and the node R4 may be an egress node or another head-
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end node. The numbers shown on each of the links between nodes
R1-R11 indicate a IS-IS metric as provisioned by the operator. R1
may be configured to receive TE source routed path information from a
central entity (PCE or Controller) that comprise NSP information
which relates to sources that are attached to R1. It is also
possible to have an NSP provisioned locally by the operator for non-
TE needs (FRR or for chaining certain services). The NSP information
is encoded as an ordered list of segments from source to a
destination node in the network and is represented with an NSPF-ID.
The NSP information includes NSP sub-TLVS which represents both
topological and non-topological segments and specifies the actual
path towards a FEC/Prefix by R4.
The shortest path towards R4 from R1 are through the following
sequence of nodes: R1-R2-R3-R4 based on the configured metrics. The
central entity may define a few NSPs from R1 to R4 that deviate from
the shortest path based on other network characteristic requirements
as requested by an application or service. For example, the network
characteristics or performance requirements may include bandwidth,
jitter, latency, throughput, error rate, etc. A first NSP may be
identified by NSPF ID = 2 and may include the path of R1-R6-R7-R4 for
a FEC Prefix advertised by R4. A second NSP may be identified by
NSPF ID = 3 and may include the path of R1-R8-R9-R10-R4. Though
these example shows NSP with all nodal SIDs, it is possible to have
an NSP with combination of node and adjacency SIDS (local or global)
or with non-topological segments along with these.
Each receiving node, determine whether an advertised NSP includes
information regarding the receiving node. This MAY be done, during
the end of the SPF computation for MTID that is advertised in this
TLV and for the FEC/Prefix. For example, node R9 receives the NSP
information, and ignores the first NSP identified by NSPF ID = 2
because this NSP does not include node R9.
However, node R9 may determine that the second NSP identified by NSPF
ID = 3 does include the node R9 for the FEC prefix advertised by R4.
Therefore, node R9 updates the local forwarding database to include
an entry for the destination address of R4 that indicates, that when
a data packet comprising a NSPF-ID of 3 is received, forward the data
packet to node R10 instead of R11. This is even though from R9 the
shortest path cost to reach R4 via R11 is 3 (R9-R11-R12-R4) it
chooses the nexthop to R10 to reach R4 as specified in the NSP. Same
process happens to all the nodes on the NSP.
In summary, the receiving node checks if this node is on the path, if
yes, it adjusts the shortest path nexthop computed towards "FEC
Prefix" to the shortest path nexthop towards the next segment as
specified in the NSP.
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4. NSPF ID Data Plane aspects
Data plane NSPF ID is selected by the entity (e.g., a controller,
locally provisioned) which selects a particular NSP in the network.
Section 2.2 defines various data plane identifier types and a
corresponding data plane identifier type and identifier is selected
by the entity which selects the NSP. Other data planes other than
described below can also use this TLV to describe the NSP. Further
details TBD.
4.1. MPLS Data Plane
If NSPF-ID Type is 1, the NSP belongs to SR-MPLS data plane and the
complete NSP stack is represented with a unique SR SID/Label and this
gets programmed on the data plane with the appropriate nexthop
computed as specified in Section 3 . NSP path description here is a
set of ordered SID TLVs and MAY contain both topological and non-
topological segments.
4.2. SRv6 Data Plane
If NSPF-ID Type is 4, the NSP belongs to SRv6 with SRH data plane and
the complete NSP stack is represented with IPv6 SIDs and this gets
programmed on the data plane with the appropriate nexthop computed as
specified in Section 3. NSP path description here is a set of
ordered SID TLVs and MAY contain both topological and non-topological
segments (e.g. network functions, service functions). If NSPF-ID
Type is 3 this is the traditional IPv6 mode
([I-D.ietf-dmm-srv6-mobile-uplane]) and this doesn't include SRH and
NSP stack description is similar to NSPF-ID Type 4 as described.
5. NSP Traffic Accounting
As described in Section 2.4, each node described in the NSP optional
sub-TLVs can provision the hardware to account the traffic statistics
as indicated in the non-NSP sub-TLVs for the actual data traffic.
with this more granular and dynamic enablement of traffic statistics
for only certain NSPs would be possible. This approach, thus is more
safe and secure than any mechanism that involves creating state in
the nodes with data traffic itself. This is because creation and
deletion of the traffic accounting state for NSPs happen through IS-
IS LSP processing and IS-IS security Section 8 options are applicable
to this TLV.
How the traffic accounting is distributed to a central entity is out
of scope of this document. One can use any method (e.g. gRPC) to
extract the NSPF-ID traffic stats from various nodes along the path.
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6. Acknowledgements
Thanks to Richard Li, Alex Clemm, Kiran Makhijani and Lin Han for
initial discussions on this topic.
Earlier versions of draft-ietf-isis-segment-routing-extensions have a
mechanism to advertise EROs through Binding SID.
7. IANA Considerations
This document requests the following new TLVin IANA IS-IS TLV code-
point registry.
TLV # Name
----- --------------
TBD NSPF ID TLV
This document also requests IANA to create new registries for NSPF-ID
Type, NSP sub-TLVs and Non-NSP sub-TLVs in NSPF ID TLV as described
in Section 2.
8. Security Considerations
Security concerns for IS-IS are addressed in [RFC5304] and [RFC5310].
Further security analysis for IS-IS protocol is done in [RFC7645].
Advertisement of the additional information defined in this document
introduces no new security concerns in IS-IS protocol. However as
this extension is related to SR-MPLS and SRH data planes as defined
in [I-D.ietf-spring-segment-routing], those particular data plane
security considerations does apply here.
9. References
9.1. Normative References
[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>.
9.2. Informative References
[I-D.bashandy-isis-srv6-extensions]
Ginsberg, L., Bashandy, A., Filsfils, C., Decraene, B.,
and Z. Hu, "IS-IS Extensions to Support Routing over IPv6
Dataplane", draft-bashandy-isis-srv6-extensions-02 (work
in progress), March 2018.
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[I-D.hegde-spring-traffic-accounting-for-sr-paths]
Hegde, S., "Traffic Accounting for MPLS Segment Routing
Paths", draft-hegde-spring-traffic-accounting-for-sr-
paths-01 (work in progress), October 2017.
[I-D.ietf-6man-segment-routing-header]
Previdi, S., Filsfils, C., Leddy, J., Matsushima, S., and
d. daniel.voyer@bell.ca, "IPv6 Segment Routing Header
(SRH)", draft-ietf-6man-segment-routing-header-10 (work in
progress), March 2018.
[I-D.ietf-dmm-srv6-mobile-uplane]
Matsushima, S., Filsfils, C., Kohno, M., Camarillo, P.,
daniel.voyer@bell.ca, d., and C. Perkins, "Segment Routing
IPv6 for Mobile User Plane", draft-ietf-dmm-srv6-mobile-
uplane-01 (work in progress), March 2018.
[I-D.ietf-isis-mpls-elc]
Xu, X., Kini, S., Sivabalan, S., Filsfils, C., and S.
Litkowski, "Signaling Entropy Label Capability and
Readable Label-stack Depth Using IS-IS", draft-ietf-isis-
mpls-elc-03 (work in progress), January 2018.
[I-D.ietf-isis-segment-routing-extensions]
Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A.,
Gredler, H., Litkowski, S., Decraene, B., and J. Tantsura,
"IS-IS Extensions for Segment Routing", draft-ietf-isis-
segment-routing-extensions-15 (work in progress), December
2017.
[I-D.ietf-isis-segment-routing-msd]
Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg,
"Signaling MSD (Maximum SID Depth) using IS-IS", draft-
ietf-isis-segment-routing-msd-09 (work in progress),
January 2018.
[I-D.ietf-spring-segment-routing]
Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B.,
Litkowski, S., and R. Shakir, "Segment Routing
Architecture", draft-ietf-spring-segment-routing-15 (work
in progress), January 2018.
[RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
Topology (MT) Routing in Intermediate System to
Intermediate Systems (IS-ISs)", RFC 5120,
DOI 10.17487/RFC5120, February 2008,
<https://www.rfc-editor.org/info/rfc5120>.
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[RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic
Authentication", RFC 5304, DOI 10.17487/RFC5304, October
2008, <https://www.rfc-editor.org/info/rfc5304>.
[RFC5310] Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,
and M. Fanto, "IS-IS Generic Cryptographic
Authentication", RFC 5310, DOI 10.17487/RFC5310, February
2009, <https://www.rfc-editor.org/info/rfc5310>.
[RFC7413] Cheng, Y., Chu, J., Radhakrishnan, S., and A. Jain, "TCP
Fast Open", RFC 7413, DOI 10.17487/RFC7413, December 2014,
<https://www.rfc-editor.org/info/rfc7413>.
[RFC7645] Chunduri, U., Tian, A., and W. Lu, "The Keying and
Authentication for Routing Protocol (KARP) IS-IS Security
Analysis", RFC 7645, DOI 10.17487/RFC7645, September 2015,
<https://www.rfc-editor.org/info/rfc7645>.
[RFC7794] Ginsberg, L., Ed., Decraene, B., Previdi, S., Xu, X., and
U. Chunduri, "IS-IS Prefix Attributes for Extended IPv4
and IPv6 Reachability", RFC 7794, DOI 10.17487/RFC7794,
March 2016, <https://www.rfc-editor.org/info/rfc7794>.
Authors' Addresses
Uma Chunduri (editor)
Huawei USA
2330 Central Expressway
Santa Clara, CA 95050
USA
Email: uma.chunduri@huawei.com
Jeff Tantsura
Nuage Networks
755 Ravendale Drive
Mountain View, CA 94043
USA
Email: jefftant.ietf@gmail.com
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Yingzhen Qu
Huawei USA
2330 Central Expressway
Santa Clara, CA 95050
USA
Email: yingzhen.qu@huawei.com
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