| Networking Working Group | Yongqing. Zhu |
| Internet-Draft | China Telecom |
| Intended status: Standards Track | Ran. Chen |
| Expires: January 7, 2020 | Shaofu. Peng |
| ZTE Corporation | |
| July 6, 2019 |
IS-IS Extensions to Support Packet Network Slicing using Segment Routing
draft-zch-lsr-isis-network-slicing-01
[I-D.peng-lsr-network-slicing] defines a unified administrative instance identifier to distinguish different virtual network resources for both intra-domain and inter-domain network slicing scenarios. This draft describes the IS-IS extensions required to support Packet Network Slicing using Segment Routing.
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For a packet network, network slicing requires the underlying network to support partitioning of the network resources to provide the client with dedicated (private) networking, computing, and storage resources drawn from a shared pool. The slices may be seen as virtual networks. [I-D.ietf-teas-enhanced-vpn] described a framework to create virtual networks in a packet network. [I-D.peng-lsr-network-slicing] specifies a detailed mechanism to signal association of shared resources required to create and manage an NSI called "Administrative Instance Identifier" (AII).
This draft describes the IS-IS extensions required to distribute AII information in an AS.
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.
[RFC5305] describes extensions to the Intermediate System to Intermediate System (IS-IS) protocol to support Traffic Engineering (TE).
AII can be used to color links to partition underlay resource. This document defines a new extension of the existing IGP-TE mechanisms[RFC5305] to distribute AII information in an AS as a new TE parameter of a link.
The AII list sub-TLV 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=TBD1 | Length | Reserved | Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AII for virtual networks 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ...... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AII for virtual networks N |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1
Type: 43 (Suggested value to be assigned by IANA)
Length: variable.
Number:Number of virtual networks.
AII for VN: allocate different AII for different virtual networks. AII is used to distinguish different virtual network resources.
This sub-TLV MAY be present in any of the following TLVs:
TLV-22 (Extended IS reachability) [RFC5305].
TLV-222 (Multitopology IS)[RFC5120].
TLV-23 (IS Neighbor Attribute)[RFC5311].
TLV-223 (Multitopology IS Neighbor Attribute)[RFC5311].
TLV-141 (inter-AS reachability information)[RFC5316].
This sub-TLV SHOULD appear once at most in each TLV. Indicates that a link MAY belong to multiple virtual networks.
Note that AII 0 does not require notification, and all links are always in AII 0 at the same time.
[I-D.ietf-isis-segment-routing-extensions] defines a new IS-IS sub-TLV: the Prefix Segment Identifier sub-TLV (Prefix-SID sub-TLV). The Prefix-SID sub-TLV carries the Segment Routing IGP-Prefix-SID as defined in [RFC8402], and is associated to a prefix advertised by a node.
To distinguish forwarding behavior of different virtual networks, Prefix-SID need to be allocated per AII and advertised in the IGP domain. This document defines a new extension of the existing Prefix-SID sub-TLV.
The Prefix-SID for AII sub-TLV 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=TBD2 | Length | Flag | Algorithm |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AII |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID/Index/Label(Variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2
where:
Type:33 (Suggested value to be assigned by IANA)
Length: Variable. Depending on the size of the SID.
The "Flags" and "SID/Index/Label" fields are the same as the Prefix-SID sub-TLV [I-D.ietf-isis-segment-routing-extensions].
AII: Identifies the AII information corresponding to the Prefix-SID.
This sub-TLV MAY be present in any of the following TLVs:
TLV-135 (Extended IPv4 reachability) defined in [RFC5305].
TLV-235 (Multitopology IPv4 Reachability) defined in [RFC5120].
TLV-236 (IPv6 IP Reachability) defined in [RFC5308].
TLV-237 (Multitopology IPv6 IP Reachability) defined in [RFC5120].
This sub-TLV MAY appear multiple times in each TLV.
[I-D.ietf-isis-segment-routing-extensions]defines a new IS-IS sub-TLV: the Adjacency Segment Identifier sub-TLV (Adj-SID sub-TLV).The Adj-SID sub-TLV is an optional sub-TLV carrying the Segment Routing IGP-Adjacency-SID as defined in [RFC8402].
To distinguish forwarding behavior of different virtual networks, Adjacency -SID need to be allocated per AII and advertised in the IGP domain. This document defines a new extension of the existing Adjacency-SID sub-TLV.
The Adjacency-SID for AII sub-TLV 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=TBD3 | Length | Flag | Algorithm |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AII |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SID/Index/Label(Variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3
where:
Type:44 (Suggested value to be assigned by IANA)
Length: Variable. Depending on the size of the SID.
The "Flags" and "SID/Index/Label" fields are the same as the Adjacency-SID sub-TLV [I-D.ietf-isis-segment-routing-extensions].
AII: Identifies the AII information corresponding to the Adjacency-SID.
This sub-TLV MAY be present in any of the following TLVs:
TLV-22 (Extended IS reachability) [RFC5305].
TLV-222 (Multitopology IS)[RFC5120].
TLV-23 (IS Neighbor Attribute)[RFC5311].
TLV-223 (Multitopology IS Neighbor Attribute)[RFC5311].
TLV-141 (inter-AS reachability information)[RFC5316].
Multiple Adj-SID sub-TLVs MAY be associated with a single IS-neighbor. This sub-TLV MAY appear multiple times in each TLV.
This document requests allocation for the following Sub-TLVs.
This TLV shares sub-TLV space with existing "Sub-TLVs for TLVs 22, 222, 23,223 and 141 registry".
Type:43(suggested - to be assigned by IANA).
This TLV shares sub-TLV space with existing "Sub-TLVs for TLVs 135,235,226 and 237 registry".
Type:33(suggested - to be assigned by IANA).
This TLV shares sub-TLV space with existing "Sub-TLVs for TLVs 22, 222, 23,223 and 141 registry".
Type:44(suggested - to be assigned by IANA).
TBD.
TBD.
| [I-D.peng-lsr-network-slicing] | Peng, S., Chen, R. and G. Mirsky, "Packet Network Slicing using Segment Routing", Internet-Draft draft-peng-lsr-network-slicing-00, February 2019. |