Internet DRAFT - draft-zhang-tvr-routing-considerations
draft-zhang-tvr-routing-considerations
TVR Z. Zhang
Internet-Draft Y. Wei
Intended status: Informational ZTE Corporation
Expires: 10 January 2024 9 July 2023
The routing considerations for TVR
draft-zhang-tvr-routing-considerations-00
Abstract
Time-Variant Routing (TVR) introduces a scenario of calculating a
path, or sub-path within a network, taking into account the timing of
message transmission or receipt as an integral part of the overall
route computation. This document introduces three modes of routing
computation for TVR scenario.
Status of This Memo
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This Internet-Draft will expire on 10 January 2024.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Each node gets the models directly . . . . . . . . . . . . . 2
3. VN advertises the variability by typical advertisement . . . 3
4. Helper advertises the variability by typical advertisement . 3
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
6. Security Considerations . . . . . . . . . . . . . . . . . . . 3
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 3
7.1. Normative References . . . . . . . . . . . . . . . . . . 3
7.2. Informative References . . . . . . . . . . . . . . . . . 3
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
Time-Variant Routing (TVR) introduces a scenario of calculating a
path, or sub-path within a network, taking into account the timing of
message transmission or receipt as an integral part of the overall
route computation. [I-D.ietf-tvr-use-cases] introduces typical TVR
use cases and analyses the routing impacts. The routing computation
is influenced by the parameters include links, adjacencies and costs,
etc. [I-D.qu-tvr-schedule-yang] defines the YANG model which
specifies a recurring schedule for changing the attributes of
resources used for TVR scenario.
This document introduces three modes of routing computation for TVR
scenario. Each node influenced by the TVR parameters can computes
the routes correctly, predictably and precisely.
For the convenience, the node with scheduled variation of link or
cost, is called Variable Node. The VN may or may not have routing
capabilities, such as routing advertisement or routing computation.
2. Each node gets the models directly
Each node in the TVR scenario gets the YANG model which defined in
[I-D.qu-tvr-schedule-yang] directly from the controller, or by any
other ways such as configuration. The YANG model needs to be
translated to the items of database, such as route-LSA in OSPF, or
LSP in IS-IS. All the nodes need to understand the YANG model and do
the translating work, then the nodes can compute the predictable
routing table. In this case, whether the VN has or has not routing
capabilities does not have influence.
This mode applies to all the use cases described in
[I-D.ietf-tvr-use-cases].
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3. VN advertises the variability by typical advertisement
In this case, the VN has the routing capabilities, it can advertise
the routing variability to all the other nodes in TVR scenario.
Before the predicted time, the VN advertises variabilities include
link, adjacency or cost to other nodes by typical advertisement.
In this case, except the VN, other nodes need not to get or translate
the model from controller or by configuration. But the advanced time
needs to be ensured, and there may be computation latency for
variable node.
This mode applies to the use case described in section 4 in
[I-D.ietf-tvr-use-cases].
4. Helper advertises the variability by typical advertisement
In this case, some nodes which are called helpers, can do the typical
advertisement instead of the VN. The helper usually is the adjacency
routing node to the VN.
Before the predicted time, the helper advertises the variability from
the perspective of itself to the other nodes in the TVR scenario.
For example, in the predictable time, the link of VN is down, the
helper advertises the link or adjacency variability of itself. The
helper node and other nodes can compute the routing table correctly.
In this case, except the helper node, other nodes need not to get or
translate the model from controller or by configuration. But the
advanced time needs to be ensured, and there may be computation
latency for variable node.
This mode applies to the use case described in section 3 and section
5 in [I-D.ietf-tvr-use-cases].
5. IANA Considerations
This document has no IANA actions.
6. Security Considerations
TBD.
7. References
7.1. Normative References
7.2. Informative References
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[I-D.ietf-tvr-use-cases]
Birrane, E. J., Kuhn, N., and Y. Qu, "TVR (Time-Variant
Routing) Use Cases", Work in Progress, Internet-Draft,
draft-ietf-tvr-use-cases-01, 3 July 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-tvr-use-
cases-01>.
[I-D.qu-tvr-schedule-yang]
Qu, Y., Lindem, A., and M. Blanchet, "YANG Model for
Scheduled Attributes", Work in Progress, Internet-Draft,
draft-qu-tvr-schedule-yang-00, 7 July 2023,
<https://datatracker.ietf.org/doc/html/draft-qu-tvr-
schedule-yang-00>.
Authors' Addresses
Zheng(Sandy) Zhang
ZTE Corporation
China
Email: zhang.zheng@zte.com.cn
Yuehua Wei
ZTE Corporation
Email: wei.yuehua@zte.com.cn
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