Internet DRAFT - draft-compute-aware-advertise-route-san-database
draft-compute-aware-advertise-route-san-database
INTAREA F. Zhou
Internet-Draft D. Yuan
Intended status: Standards Track ZTE Corporation
Expires: 13 April 2023 10 October 2022
Computing Status Awareness, Advertisement and Service Routing methods of
SAN Based on Databases
draft-compute-aware-advertise-route-san-database-00
Abstract
This draft proposes a unified method to perceive and advertise the
running status of computing resources in a Service Awareness Network
by introducing a distributed database. The forwarding operation in a
fine-grained service routing policy is correspondingly defined which
is completely decoupled from conventional IP routing. In the scheme
proposed, the impact of high frequency changes of computing resources
is avoided and the compatibility of the network is enhanced.
Status of This Memo
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This Internet-Draft will expire on 13 April 2023.
Copyright Notice
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document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. The Perception of the Status of Computing Resources . . . . . 5
5. The Advertisement of the Status of Computing Resources . . . 6
6. Service Routing Decoupled from IP Routing . . . . . . . . . . 7
7. Use Case . . . . . . . . . . . . . . . . . . . . . . . . . . 9
8. Security Considerations . . . . . . . . . . . . . . . . . . . 10
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
11. Normative References . . . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction
With computing resource continuously migrating to edges, services
residing distributedly turns to be delivered in a dynamic way. More
fine-grained networking policies awaring of service SLA requirements
are urgently required.
As illustrated in [I-D.huang-service-aware-network-framework], a
typical SAN framework consists of service client, service server, SAN
ingress, SAN relay and SAN egress. A fine-grained networking policy
can be achieved through successive procedures:
* The perception of the status of computing resources: Changes and
variations in the current status of computing resources should be
notified and reflected. Static configurations together with the
dynamic changes comprise a thorough and overall view as a
reference to select a proper resource pool.
* The advertisement of the status of computing resources: A group of
nodes in the network domain should further be aware of the current
distributions and conditions among various resource pools so that
the networking and routing policies can be adjusted or formulated.
The advertisement of the running status is also a learning
procedure for the network domain.
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* The formulation of a specific service routing policy: With the
knowledge of the running status and network conditions, an
appropriate resource pool can be selected to satisfy the service
SLA requirements. A specific fine-grained service routing policy
can further be formulated to forward the packets.
The mentioned procedures are shown in Figure 1:
(1)Perception<---------------------+
| |
v |
(2)Advertisement |
| Status of|
+---------------+--------------+ Computing|
| | | Resources|
v v v |
|
(3)Service Routing |
+-------+ --------> +-------+
|Service| +-----------+ +----------+ +----------+ |Service|
| +----+SAN Ingress+---+SAN Relay+---+SAN egress+---+ |
|Client | +-----------+ +----------+ +----------+ |Server |
+-------+ | +-------+
| | |
| | |
| |<-----SAN Fowarding and Routing Domain---->|
| |
| |
|<---------------Service Identification Domain------------>|
Figure 1: Computing Resource Perception and Advertisement in SAN
Since the perception and advertisement procedures are the premises to
achieve service routing, enabling the network to be aware of the
running status timely is regarded to be a significant problem.
Currently, the perception of computing resources can be commonly
achieved by application protocols, FTP for instance. With the
connection between clients and the server establishd, the cloud side
is required to spontaneously upload the running status of computing
resources. The process of advertising computing resource information
is commonly fulfilled by extending IGP or BGP. Packets with a
designated format carrying information of computing resources flood
in the network to complete the learning process.
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In current schemes, service routing is strongly coupled with
traditional IP routing which results in the following deficiencies:
* The status of computing resources is updated with delay attributed
to a relatively long authentication duration and the usage of
multiple protocols.
* Responses in the network to the highly dynamic computing resources
is relatively slow by using IGP or BGP.
* Compared to conventional IP routing, service routing is
comprehensively designated by both network metrics and service SLA
requirements in which the status of computing resources is highly
dynamic. Thus, advertising the dynamic status emerge a large
amount of extra packets and exert relatively severe impact on the
traffic bearer in the current network. Furthermore, conventional
network services are not concerned about the status of computing
resource.
According to the analysis above, the following problems are required
to be solved:
* Reduce the overwhelmed utilization of L3 protocols and improve the
compatibility of the network.
* Simplify the perception and advertisement process and optimize the
learning procedure of updated status.
This draft proposes computing resources perception and advertisement
method by introducing a distributed database to fulfill service
routing decoupled from conventional IP routing.
2. 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.
3. Terminology
* LB: Load Balancer
* FTP: File Transfer Protocol
* IGP: Interior Gateway Protocol
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* BGP: Border Gateway Protocol
* DB-Agent: Agent of a database
* GW: Gateway
* SLA: Service Level Agreements
* SID: Segment ID
* SAN: Service Awareness Network
* SAN ID: Service Awareness Network Identification, an
identification designed to indicate the fundamental and common
service types
4. The Perception of the Status of Computing Resources
The computing resources information of the cloud-side server is used
to reflect the performance and a running status of resource pools.
It is obtained to facilitate unified collaborative invocation of
computing power resources.
It is noted that identical services can be provided by multiple
resource pools which connects to different gateways and status of
resource pools varies from each other. Thus, the description of
computing resource may include the following attributes as shown in
Figure 2:
+------------+-----------------+-----------------------------------+
| SAN ID | Service Gateway | Service Descriptions Index(1-n) |
+------------+-----------------+-----------+-----------+-----------+
| Service 1 | GW1 | CPU 1 | Memory 1 | O/I 1 |
+------------+-----------------+-----------+-----------+-----------+
| Service 2 | GW2 | CPU 2 | Memory 2 | O/I 2 |
+------------+-----------------+-----------+-----------+-----------+
| Service 3 | GW2 | CPU 3 | Memory 3 | O/I 3 |
+------------+-----------------+-----------+-----------+-----------+
| Service 3 | GW3 | CPU 4 | Memory 4 | O/I 4 |
+------------+-----------------+-----------+-----------+-----------+
| Service 1 | GW3 | CPU 5 | Memory 5 | O/I 5 |
+------------+-----------------+-----------+-----------+-----------+
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Figure 2: Status Table of Computing Resources
Since the status of computing resources can be modeled as a
collection of key-value pairs with keys as unique identifiers, this
draft introduced a distributed database to store and update the
running status. As shown in Figure 2, a service identification
defined as a SAN ID(Service ID) in
[I-D.service-identification-header-of-san] to represent a globally
unique service semantic identification and its connected gateway
should be configured as the key for the extracted data model.
A distributed system has the advantages of advanced performance, high
availability and simple extensibility. It is highly partitionable
and allows horizontal scaling which satisfies the practical scenarios
of large scale of service instances. Also, both keys and values can
be anything from simple objects to complex compound objects, and thus
heterogeneous computing resources can be described and stored.
After the key-value pairs are extracted and further written into the
database by the cloud side as multiple DB-Agents, the perception of
the status of computing resources is fulfilled.
5. The Advertisement of the Status of Computing Resources
+-------------+
| +--------+| +-----------------------------+
|VM |Database||<---------------------| DB-Agent |
| +--------+| Write | |
+-------------+ | +---------+ |
| Read | +--------+Service 1| |
v | | +---------+ |
+----------------------+ | +------+------+ |
| DB-Agent | | |Load Balancer| ...... |
| | | +------+------+ |
| +----+ +----+ | | | +---------+ |
| |PE 1| ...... |PE n| | | +--------+Service n| |
| +----+ +----+ | | +---------+ |
| | | |
| Network Edge Devices | | Cloud |
+----------------------+ +-----------------------------+
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Figure 3: The status of computing resources learning procedures
With the introduction of a distributed database, the data of the
computing resources can be stored in hierarchically organized
directories. A typical form is described as below:
* /service instances/GW
* /service instances/SAN ID
* /service instances/SAN ID/CPU Load
* /service instances/SAN ID/Memory Remains
As shown in Figure 3, a group of edge devices in the network domain
observes the key value information through a publish-subscribe
mechanism. Specific keys or directories can be watched for changes
and multiple clients can react to changes in values. Since multiple
edge devices simultaneously observe the variations, the running
status is advertised to all edge devices. It is concluded that, by
introducing a database, functions of perception and advertisement are
unified.
It can be understood that in the mentioned writing and reading
process, there is no necessity to perform additional authentication
on a management protocol and network layer protocols, thereby
simplifying the overall procedure.
6. Service Routing Decoupled from IP Routing
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+-----------------------------+
| DB-Agent |
|+---------------------------+|
|| Computing Resource & ||
|| Network Information ||
|| Perception Module ||
|+---------------------------+|
+-----------------------------+
| +-------------------------+
|<-------------------| Networking Policy |
| +-------------------------+
| +-------------------------+
|<-------------------|Service Addressing Policy|
| +-------------------------+
v
+-----------------------+ +------------------+
| Service Routing Table +<------------------>+ IP Routing Table |
+-----------------------+ +------------------+
Figure 4: Service Routing Decoupled from IP Routing
As shown in Figure 4, after the current computing status is obtained,
a proper resource pool can be selected to satisfy the service SLA
requirements, so as to quickly and accurately guide data forwarding.
Together with path metrics in the network, a specific service routing
table is formulated.
Since the service routing table is generated additionally, it is
completely decoupled from the conventional IP routing table. As
shown in Figure 5, for services with requirements for computing
resources, the service routing table maps to the IP routing table to
complete a forwarding operation. With the service gateway
determined, an Interface IP or an SRv6 policy can be indexed. For
conventional services which are not sensitive to computing resources,
a forwarding operation can be implemented simply in the original way.
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Service Routing Table IP Routing Table
+------------+-----------------+ +---------------+--------------+
| Service ID | Service Gateway | |Prefix(Gateway)| Next Hop |
+------------+-----------------+ +---------------+--------------+
| Service 1 | GW1 (Node SID1) |<-->| GW1 | Interface IP |
+------------+-----------------+ +---------------+--------------+
| Service 2 | GW2 (Node SID2) | | | SRv6 Policy |
+------------+-----------------+<-->| GW2 | (Endpoint+ |
| Service 3 | GW2 (Node SID2) | | | Color) |
+------------+-----------------+ +---------------+--------------+
Figure 5: Service Routing Table Maps to IP Routing Table
With the introduction of a distributed database, the service routing
procedure is decoupled from traditonal IP routing which enhances the
compatibility of different services carried in the network.
7. Use Case
As shown in Figure 6, suppose CPU load is a sample attribute and 70%
is configured to be a threshold. If the CPU load beyonds 70%, the
traffic needs to be steered to another satisfied resource pool .
The procedure of learning and processing updated computing resource
status is described as follows:
* The CPU load of the container or VM where the service instance is
located reaches the threshold 70% and the updated status is then
written into the database in a key-value model.
* Edge devices in the network domain subscribe the information by
watching the prefix of the key-value pair.
* Any variations in the subscribed information can be perceived and
further learned by the edge devices.
* Learning the CPU load reaches 70%, the service routing table is
updated or regenerated.
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Network Domain Cloud Domain
+-------------------------+ +-----------------------+
|+------------+ +--------+| +--------+ |+--------+ +----------+|
||Edge Devices| |DB-Agent|| |Database| ||DB-Agent| |Cloud Side||
|+------------+ +--------+| +--------+ |+--------+ +----------+|
+-------------------------+ +-----------------------+
| | |<-------------| |
| | | | |
| | watch | (/Service | |
| | (/Service | Instances/ | |
| | Instances | CPU Load 70) | |
| | prefix/) | | |
| |------------>| | |
| | | | |
| |<------------| | |
| | notify | | |
|notify | (/Service | | |
|(/Service | Instances | | |
|Instances/ | prefix/) | | |
|SAN ID/ | | | |
|CPU Load 70)| | | |
|<-----------| | | |
| | | | |
Figure 6: An Example of Database-Based Computing Resource
Perception Procedure
8. Security Considerations
TBA
9. Acknowledgements
TBA
10. IANA Considerations
TBA
11. Normative References
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[I-D.huang-service-aware-network-framework]
Huang, D. and B. Tan, "Service Aware Network Framework",
Work in Progress, Internet-Draft, draft-huang-service-
aware-network-framework-00, 24 May 2022,
<https://www.ietf.org/archive/id/draft-huang-service-
aware-network-framework-00.txt>.
[I-D.service-identification-header-of-san]
Ma, L., Zhou, F., and H. Li, "Service Identification
Header of Service Aware Network", Work in Progress,
Internet-Draft, draft-service-identification-header-of-
san-00, 18 August 2022, <https://www.ietf.org/archive/id/
draft-service-identification-header-of-san-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>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
Authors' Addresses
Fenlin Zhou
ZTE Corporation
No.50 Software Avenue
Nanjing
Jiangsu, 210012
China
Email: zhou.fenlin@zte.com.cn
Dongyu Yuan
ZTE Corporation
No.50 Software Avenue
Nanjing
Jiangsu, 210012
China
Email: yuan.dongyu@zte.com.cn
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