INTAREA Working Group A. Ghule
Internet-Draft R. Bonica
Intended status: Experimental Juniper Networks
Expires: February 8, 2020 August 7, 2019
Use of The IPv4 Reserved-flag for OAM
draft-aghule-intarea-oam-01
Abstract
This document defines new IPv4 Operations and Management (OAM)
capabilities. In order to support these capabilities, this document
defines a new interpretation of the IPv4 Reserved-flag.
Status of This Memo
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Table of Contents
1. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 2
3. Redefining the IPv4 Reserved-Bit . . . . . . . . . . . . . . 2
4. OAM Flag Processing . . . . . . . . . . . . . . . . . . . . . 3
4.1. At Network Ingress Nodes . . . . . . . . . . . . . . . . 3
4.2. At Network Interior Nodes . . . . . . . . . . . . . . . . 3
4.3. At Network Egress Nodes . . . . . . . . . . . . . . . . . 4
5. The ICMP OAM Message . . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . 6
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
9.1. Normative References . . . . . . . . . . . . . . . . . . 6
9.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Problem Statement
This document defines new IPv4 [RFC0791] Operations and Management
(OAM) capabilities. In order to support these capabilities, this
document defines a new interpretation of the IPv4 Reserved-flag.
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. Redefining the IPv4 Reserved-Bit
0 1 2
+---+---+---+
| | D | M |
| 0 | F | F |
+---+---+---+
Figure 1: Current Defintion Of The IPv4 Flags Field
Figure 1 depicts the IPv4 Flags field, as defined in [RFC0791]. It
contains the following fields:
o Bit 0: reserved, must be zero
o Bit 1: (DF) 0 = May Fragment, 1 = Don't Fragment.
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o Bit 2: (MF) 0 = Last Fragment, 1 = More Fragments.
0 1 2
+---+---+---+
| O | D | M |
| A | F | F |
| M | | |
+---+---+---+
Figure 2: Redefintion Of The IPv4 Flags Field
Figure 2 depicts a redefinition of the IPv4 flags field. It contains
the following fields:
o Bit 0: OAM 0 = No OAM Action, 1 = OAM Action
o Bit 1: (DF) 0 = May Fragment, 1 = Don't Fragment.
o Bit 2: (MF) 0 = Last Fragment, 1 = More Fragments.
In the redefinition, the Reserved-flag is replaced by an OAM flag.
4. OAM Flag Processing
4.1. At Network Ingress Nodes
When a packet enters a provider network, the network ingress router
can subject the packet to policy. Policy includes match conditions
and actions. If the packet satisfies match conditions, the policy
can execute the following actions:
o Set the OAM-bit
o Recompute the IPv4 header checksum
If the ingress node sets the OAM bit, it MAY execute any of the OAM
actions described in Section 4.2.
4.2. At Network Interior Nodes
When a network interior node receives a packet and its OAM bit is
set, it MAY execute any combination of the following OAM actions.
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+-----------+-------------------------------------------------------+
| Action | Notes |
+-----------+-------------------------------------------------------+
| Log the | The processing node creates a log entry. The log |
| packet | entry reflects the time at which it was created. It |
| | also reflects the time at which the packet arrived. |
| | |
| Count the | The processing node increments a counter. |
| packet | |
| | |
| Send an | The processing node sends an ICMP OAM message to the |
| ICMP OAM | packet's source. The OAM message indicates the time |
| message | at which the packet arrived. |
| | |
| Send | The processing node sends telemetry to a monitoring |
| telemetry | station. Telemetry includes the packet and the time |
| | at which the packet arrived. |
+-----------+-------------------------------------------------------+
Table 1: OAM Actions
The action taken depends on local configuration. By default, no
action is taken
4.3. At Network Egress Nodes
When a network egress node receives a packet and the OAM bit is set,
it MAY execute any of the OAM actions described in Section 4.2. It
SHOULD clear the OAM bit. If it clears the OAM bit, it MUST
recompute the IPv4 Header Checksum.
5. The ICMP OAM Message
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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 | Code | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp (seconds) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp (fraction) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Original Datagram +
| |
Figure 3
Figure 3 depicts the ICMP OAM message. The ICMP OAM message contains
the following fields:
o Type - OAM. Value TBD by IANA.
o Code - MUST be set to (0) No Error.
o Checksum - See [RFC0792]
o Reserved - MUST be set to 0 and MUST be ignored upon receipt.
o Length - Represents the length of the padded "original datagram"
field, measured in 32-bit words.
o Timestamp (seconds) - Represents the time at which the original
packet arrived in Network Time Protocol (NTP) [RFC5905] format.
o Timestamp (fraction) - Represents the time at which the original
packet arrived in NTP [RFC5905] format.
o Original Datagram - As much of invoking packet as possible without
the ICMPv6 packet exceeding the minimum ICMP MTU (576 bytes). The
original datagram MUST be zero padded to the nearest 32-bit
boundary.
ICMP OAM messages SHOULD be rate limited by the sender.
The Timestamp fields SHOULD be as accurate as possible. They SHOULD
reflect the time at which the original packet arrived, not the time
at which the ICMPv6 OAM message was sent.
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6. IANA Considerations
IANA is requested to add an entry to the ICMP Type registry
(https://www.iana.org/assignments/icmp-parameters/icmp-
parameters.xhtml#icmp-parameters-types). The ICMP message name is
OAM and its value is TBD by IANA.
7. Security Considerations
All OAM actions elicited by the OAM bit must be rate-limited, so that
they cannot be used as denial of service attack vectors.
8. Acknowledgements
The authors wish to acknowledge Ross Callon for his contributions to
this document.
9. References
9.1. Normative References
[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,
DOI 10.17487/RFC0791, September 1981,
<https://www.rfc-editor.org/info/rfc791>.
[RFC0792] Postel, J., "Internet Control Message Protocol", STD 5,
RFC 792, DOI 10.17487/RFC0792, September 1981,
<https://www.rfc-editor.org/info/rfc792>.
[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>.
[RFC5905] Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch,
"Network Time Protocol Version 4: Protocol and Algorithms
Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010,
<https://www.rfc-editor.org/info/rfc5905>.
[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>.
9.2. Informative References
[InfRef] , 2004.
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Authors' Addresses
Ashish Ghule
Juniper Networks
Bangalore, KA 56009
India
Email: aghule@juniper.net
Ron Bonica
Juniper Networks
Herndon, Virginia 20171
USA
Email: rbonica@juniper.net
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