Internet DRAFT - draft-penno-sfc-trace
draft-penno-sfc-trace
SFC Netmod R. Penno
Internet-Draft P. Quinn
Intended status: Standards Track C. Pignataro
Expires: April 2, 2016 Cisco Systems
D. Zhou
Intel Corporation
September 30, 2015
Services Function Chaining Traceroute
draft-penno-sfc-trace-03
Abstract
This document defines a protocol that checks the liveness and report
the service-hops of a service path. .
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
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Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 2, 2016.
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
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publication of this document. Please review these documents
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Definitions and Acronyms . . . . . . . . . . . . . . . . . . 2
3. SFC Trace . . . . . . . . . . . . . . . . . . . . . . . . . . 2
4. Service Function Behavior . . . . . . . . . . . . . . . . . . 6
5. Service Function Forwarder Behavior . . . . . . . . . . . . . 6
6. Implementation . . . . . . . . . . . . . . . . . . . . . . . 7
7. SFC Reverse Trace . . . . . . . . . . . . . . . . . . . . . . 7
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
9. Security Considerations . . . . . . . . . . . . . . . . . . . 7
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
11. Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
12.1. Normative References . . . . . . . . . . . . . . . . . . 7
12.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
This document defines a protocol that allows a user to check liveness
and get reports of the service-hops of a service path
2. Definitions and Acronyms
The reader should be familiar with the terms contained in
[I-D.ietf-sfc-architecture], ,[I-D.ietf-sfc-architecture] and
[I-D.quinn-vxlan-gpe]
3. SFC Trace
A trace packet uses the same NSH header as MD-type 1 with a few
differences: OAM Bit and Next Protocol.
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SFC Trace Request packet format
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+\
|Ver|1|C|R|R|R|R|R|R| Length | MD-type=0x1 | OAM Protocol | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Service Path ID | Service Index | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Mandatory Context Header | |S
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |F
| Mandatory Context Header | |C
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Mandatory Context Header | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Mandatory Context Header | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ <
|Trace Msg Type | SIL | Dest Port | |O
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |A
| Dest IP Address | |M
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Dest IP Address | |T
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |R
| Dest IP Address | |A
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |C
| Dest IP Address | |E
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+/
(postamble)
Ver: 1
OAM Bit: 1
Length: 6
MD-Type: 1
Next Protocol: OAM Protocol
Trace Msg Type: 1 for Trace Request and 2 for Trace Report
SIL: Service Index Limit: At least one less than the Starting Index
Dest Port: The trace report must be sent to this destination Port
Dest IP: the trace report must be sent to this destination IP
address
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For simplicity in building and parsing request and response packets,
NSH Trace always uses fixed-size 128-bit IP address fields for both
IPv6 addresses and IPv4 addresses.
When the address field holds an IPv6 address, the fixed-size 128-bit
IP address field holds the IPv6 address stored as is.
When the address field holds an IPv4 address, an IPv4-mapped IPv6
address [RFC4291] is used (::ffff:0:0/96). This has the first 80
bits set to zero and the next 16 set to one, while its last 32 bits
are filled with the IPv4 address. This is unambiguously
distinguishable from a native IPv6 address, because an IPv4-mapped
IPv6 address [RFC4291] would not be valid for a mapping.
When checking for an IPv4-mapped IPv6 address, all of the first 96
bits MUST be checked for the pattern -- it is not sufficient to check
for ones in bits 81-96.
The all-zeros IPv6 address MUST be expressed by filling the fixed-
size 128-bit IP address field with all zeros (::).
The all-zeros IPv4 address MUST be expressed by 80 bits of zeros, 16
bits of ones, and 32 bits of zeros (::ffff:0:0).
Allowing the client to insert the destination IP and port where it
expects to receive reports in the NSH header allows for NAT
traversal. In other words, if the client is behind a NAT, it can
acquire a stable external IP:port and put as the destnation IP and
port in the NSH header. This would allow NSH traceroute to function
behind a NAT.
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SFC Trace Report
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+\
|Ver|1|C|R|R|R|R|R|R| Length | MD-type=0x1 | OAM Protocol | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Service Path ID | Service Index | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Mandatory Context Header | |S
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |F
| Mandatory Context Header | |C
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Mandatory Context Header | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Mandatory Context Header | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ <
|Trace Msg Type | SIL | Dest Port | |O
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |A
| Dest IP Address | |M
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Dest IP Address | |T
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |R
| Dest IP Address | |A
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |C
| Dest IP Address | |E
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+/
| SF Type Len | SF Type ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SF Name Len | SF Name ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
(postamble)
A trace report packet carries the identification of the Service
Function that last processed the packet. In all other aspects it is
exactly the same as a trace request.
SF Type Len: The Type Length in 4-byte words.
SF Type: A string representing the SF type padded to a 4-byte
boundary and encoded with UTF-8. Service types can be found and
registered in [I-D.penno-sfc-yang].
SF Name Len: The Name Length in 4-byte words.
SF Name: A string representing the Service Function padded to a
4-byte boundary and encoded with UTF-8. Service Function names
and configuration can be found in [I-D.penno-sfc-yang].
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4. Service Function Behavior
When a Service Function receives a SFC Trace request packet it
performs the following actions:
1. Decrement Service Index
2. If Service Index is equal to the Services Index Limit add its
identifying information at the end of the existing headers
3. Send packet back to Service Function Forwarder
5. Service Function Forwarder Behavior
A SFF will route trace packets based on service path ID and services
index just like any other NSH packet. This guarantees that a trace
packet follows the same path as data packets. The SFF will drop it
and generate a report only in the following conditions:
o If the SI is equal or less than SIL
o If it can not find the next service-hop.
o If a SFF receives a trace packet with SI = 0.
In the cases enumerated above the SFF will proceed as following to
build a trace report packet.
1. The SFF will use the same encapsulation as the received packet.
2. The destination IP:port will be the destination IP:port found in
the OAM Trace NSH headers
3. The entire NSH +Trace Request headers + Report section will be
copied from the received packet
4. The SFF will change the trace message type to trace report
If a SFF can not find the next service-hop for a trace packet, it
will drop the packet and generate a report packet even if SIL is
different from SI. This guarantees that the trace ends at the end of
the path irrespective if SI has reached SIL or not. More
importantly, it allow users to perform a trace that will traverse
the entire path without having to know before hand the number of
service-hops in the path by setting SIL to zero.
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6. Implementation
SFC Trace was implemented in the Opendaylight projects and output of
a 3 service-hop network can be found below.
sff_client.py --remote-sff-ip 10.0.1.41 --remote-sff-port 4789 --sfp-id 22 --sfp-index 255 --trace-req --num-trace-hops 3
Sending Trace packet to Service Path and Service Index: (22, 255)
Trace response...
Service-hop: 0. Service Type: dpi, Service Name: SF1, Address of Reporting SFF: ('10.0.1.41', 4789)
Service-hop: 1. Service Type: firewall, Service Name: SF4, Address of Reporting SFF: ('10.0.1.42', 4789)
Service-hop: 2. Service Type: napt44, Service Name: SF5, Address of Reporting SFF: ('10.0.1.43', 4789)
Trace end
Implementation guideline for the client: If the trace request has a
service index limit that would put the end of the trace beyond the
service path, for example, starting Index=255, SIL=252 but only 2
service-hops in the path, the last trace response will have no report
information. This is because no SF would detect that it is the end
of the trace and include a report information
7. SFC Reverse Trace
Tracing a reverse path by sending a packet to the forward path is not
always possible. The reason is that the sets of SFFs used in the
forward and reverse might not have common elements.
8. IANA Considerations
OAM Protocol Type and a OAM protocol Message type.
9. Security Considerations
10. Acknowledgements
11. Changes
12. References
12.1. 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,
<http://www.rfc-editor.org/info/rfc2119>.
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[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616,
DOI 10.17487/RFC2616, June 1999,
<http://www.rfc-editor.org/info/rfc2616>.
12.2. Informative References
[I-D.ietf-sfc-architecture]
Halpern, J. and C. Pignataro, "Service Function Chaining
(SFC) Architecture", draft-ietf-sfc-architecture-11 (work
in progress), July 2015.
[I-D.penno-sfc-yang]
Penno, R., Quinn, P., Zhou, D., and J. Li, "Yang Data
Model for Service Function Chaining", draft-penno-sfc-
yang-13 (work in progress), March 2015.
[I-D.quinn-sfc-nsh]
Quinn, P., Guichard, J., Surendra, S., Smith, M.,
Henderickx, W., Nadeau, T., Agarwal, P., Manur, R.,
Chauhan, A., Halpern, J., Majee, S., Elzur, U., Melman,
D., Garg, P., McConnell, B., Wright, C., and K. Kevin,
"Network Service Header", draft-quinn-sfc-nsh-07 (work in
progress), February 2015.
[I-D.quinn-vxlan-gpe]
Quinn, P., Manur, R., Kreeger, L., Lewis, D., Maino, F.,
Smith, M., Agarwal, P., Yong, L., Xu, X., Elzur, U., Garg,
P., and D. Melman, "Generic Protocol Extension for VXLAN",
draft-quinn-vxlan-gpe-04 (work in progress), February
2015.
Authors' Addresses
Reinaldo Penno
Cisco Systems
170 West Tasman Dr
San Jose CA
USA
Email: repenno@cisco.com
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Paul Quinn
Cisco Systems
170 West Tasman Dr
San Jose CA
USA
Email: paulq@cisco.com
Carlos Pignataro
Cisco Systems
170 West Tasman Dr
San Jose CA
USA
Email: cpignata@cisco.com
Danny Zhou
Intel Corporation
2200 Mission College Blvd.
Santa Clara CA
USA
Email: danny.zhou@intel.com
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