draft-ietf-idr-flow-spec-06.txt   draft-ietf-idr-flow-spec-07.txt 
IDR Working Group P. Marques IDR Working Group P. Marques
Internet-Draft N. Sheth Internet-Draft N. Sheth
Intended status: Standards Track R. Raszuk Intended status: Standards Track R. Raszuk
Expires: September 28, 2009 B. Greene Expires: October 3, 2009 B. Greene
Juniper Networks Juniper Networks
J. Mauch J. Mauch
NTT/Verio NTT/Verio
D. McPherson D. McPherson
Arbor Networks Arbor Networks
March 27, 2009 April 1, 2009
Dissemination of flow specification rules Dissemination of flow specification rules
draft-ietf-idr-flow-spec-06 draft-ietf-idr-flow-spec-07
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on September 28, 2009. This Internet-Draft will expire on October 3, 2009.
Copyright Notice Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the Copyright (c) 2009 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents in effect on the date of Provisions Relating to IETF Documents in effect on the date of
publication of this document (http://trustee.ietf.org/license-info). publication of this document (http://trustee.ietf.org/license-info).
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
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Table of Contents Table of Contents
1. Definitions of Terms Used in this Memo . . . . . . . . . . . . 4 1. Definitions of Terms Used in this Memo . . . . . . . . . . . . 4
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Flow specifications . . . . . . . . . . . . . . . . . . . . . 6 3. Flow specifications . . . . . . . . . . . . . . . . . . . . . 6
4. Dissemination of Information . . . . . . . . . . . . . . . . . 6 4. Dissemination of Information . . . . . . . . . . . . . . . . . 6
5. Traffic filtering . . . . . . . . . . . . . . . . . . . . . . 12 5. Traffic filtering . . . . . . . . . . . . . . . . . . . . . . 12
5.1. Order of traffic filtering rules . . . . . . . . . . . . . 13 5.1. Order of traffic filtering rules . . . . . . . . . . . . . 13
6. Validation procedure . . . . . . . . . . . . . . . . . . . . . 14 6. Validation procedure . . . . . . . . . . . . . . . . . . . . . 14
7. Traffic Filtering Actions . . . . . . . . . . . . . . . . . . 15 7. Traffic Filtering Actions . . . . . . . . . . . . . . . . . . 16
8. Traffic filtering in RFC2547bis networks . . . . . . . . . . . 17 8. Traffic filtering in RFC2547bis networks . . . . . . . . . . . 17
9. Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . 17 9. Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . 18
10. Security considerations . . . . . . . . . . . . . . . . . . . 18 10. Security considerations . . . . . . . . . . . . . . . . . . . 18
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 20 12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 21
13. Normative References . . . . . . . . . . . . . . . . . . . . . 20 13. Normative References . . . . . . . . . . . . . . . . . . . . . 21
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 21 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 22
1. Definitions of Terms Used in this Memo 1. Definitions of Terms Used in this Memo
NLRI - Network Layer Reachability Information NLRI - Network Layer Reachability Information
RIB - Routing Information Base RIB - Routing Information Base
Loc-RIB - Local RIB Loc-RIB - Local RIB
AS - Autonomous System Number AS - Autonomous System Number
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Match on the total IP packet length (excluding L2 but including Match on the total IP packet length (excluding L2 but including
IP header). Values are encoded using as 1 or 2 byte IP header). Values are encoded using as 1 or 2 byte
quantities. quantities.
Type 11 - DSCP Type 11 - DSCP
Encoding: <type (1 octet), [op, value]+> Encoding: <type (1 octet), [op, value]+>
Defines a list of {operation, value} pairs used to match the Defines a list of {operation, value} pairs used to match the
6-bit DSCP field. 6-bit DSCP field [RFC2474]. Values are encoded using a single
byte, where the two most significant bits are zero and the six
least significant bits contain the DSCP value.
Type 12 - Fragment Type 12 - Fragment
Encoding: <type (1 octet), [op, bitmask]+> Encoding: <type (1 octet), [op, bitmask]+>
Uses bitmask operand format defined above. Uses bitmask operand format defined above.
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+
| Reserved |LF |FF |IsF|DF | | Reserved |LF |FF |IsF|DF |
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5.1. Order of traffic filtering rules 5.1. Order of traffic filtering rules
With traffic filtering rules, more than one rule may match a With traffic filtering rules, more than one rule may match a
particular traffic flow. Thus it is necessary to define the order at particular traffic flow. Thus it is necessary to define the order at
which rules get matched and applied to a particular traffic flow. which rules get matched and applied to a particular traffic flow.
This ordering function must be such that it must not depend on the This ordering function must be such that it must not depend on the
arrival order of the flow specifications rules and must be constant arrival order of the flow specifications rules and must be constant
in the network. in the network.
We choose to order traffic filtering rules such that the order of two The relative order of two flow specification rules is determined by
flow specifications is given by the comparison of NLRI key byte comparing the their respective components. The algorithm starts by
strings as defined by the memcmp() function is the ISO C standard. comparing the left-most components of the rules. If the types
For strings of different lenghts, the common prefix is compared. If differ, the rule with lowest numeric type value has higher precedence
equal the shorter string is considered to preceed the longer one. (and thus will match before) the rule that doesn't contain that
component type. If the component types are the same, then a type
specific comparison is performed.
Given the way that flow specifications are encoded this results in a For IP prefix values (IP destination and source prefix) precedence is
flow with a less-specific destination IP prefix being considered given to lowest IP value of the common prefix length; if the common
less-than (and thus match before) a flow specification with a more- prefix is equal then the most specific prefix has precedence.
specific destination IP prefix.
This matches an application model where the user may want to define a For all other component types, unless otherwise specified, the
restriction that affects an aggregate of traffic and a subsequent comparison is performed by comparing the component data as a binary
rule that applies only to a subset of that. string using the the memcmp() function as defined by the ISO C
standard. For strings of different lenghts, the common prefix is
compared. If equal the longest string is considered to have higher
precedence than the shorter one.
A flow-specification without a destination IP prefix is considered to Pseudocode:
match after all flow-specifications that contain an IP destination
prefix. flow_rule_cmp (a, b)
{
comp1 = next_component(a);
comp2 = next_component(b);
while (comp1 || comp2) {
// component_type returns infinity on end-of-list
if (component_type(comp1) < compnent_type(comp2)) {
return A_HAS_PRECEDENCE;
}
if (component_type(comp1) > compnent_type(comp2)) {
return B_HAS_PRECEDENCE;
}
if (component_type(comp1) == IP_DESTINATION || IP_SOURCE) {
common = MIN(prefix_length(comp1), prefix_length(comp2));
cmp = prefix_compare(comp1, comp2, common);
// not equal, lowest value has precedence
// equal, longest match has precedence
} else {
common = MIN(component_length(comp1), component_length(comp2));
cmp = memcmp(data(comp1), data(comp2), common);
// not equal, lowest value has precedence
// equal, longest string has precedence
}
}
return EQUAL;
}
6. Validation procedure 6. Validation procedure
Flow specifications received from a BGP peer and which are accepted Flow specifications received from a BGP peer and which are accepted
in the respective Adj-RIB-In are used as input to the route selection in the respective Adj-RIB-In are used as input to the route selection
process. Although the forwarding attributes of two routes for the process. Although the forwarding attributes of two routes for the
same Flow Specification prefix may be the same, BGP is still required same Flow Specification prefix may be the same, BGP is still required
to perform its path selection algorithm in order to select the to perform its path selection algorithm in order to select the
correct set of attributes to advertise. correct set of attributes to advertise.
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extended community across the Autonomous system boundary and uses extended community across the Autonomous system boundary and uses
following extended community encoding: following extended community encoding:
The first two octets carry the 2 octet id which can be assigned The first two octets carry the 2 octet id which can be assigned
from a 2 byte AS number. When 4 byte AS number is locally from a 2 byte AS number. When 4 byte AS number is locally
present 2 least significant bytes of such AS number can be present 2 least significant bytes of such AS number can be
used. This value is purely informational and should not be used. This value is purely informational and should not be
interpreted by the implementation. interpreted by the implementation.
The remaining 4 octets carry the rate information in IEEE The remaining 4 octets carry the rate information in IEEE
floating point format , units being bytes per second. A floating point [IEEE.754.1985] format , units being bytes per
traffic-rate of 0 should result on all traffic for the second. A traffic-rate of 0 should result on all traffic for
particular flow to be discarded. the particular flow to be discarded.
Traffic-action The traffic-action extended community consists of 6 Traffic-action The traffic-action extended community consists of 6
bytes of which only the 2 least significant bits of the 6th byte bytes of which only the 2 least significant bits of the 6th byte
(from left to right) are currently defined. (from left to right) are currently defined.
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+
| reserved | S | T | | reserved | S | T |
+---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+
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of the traffic filter stops when this rule is applied. of the traffic filter stops when this rule is applied.
* Sample (bit 6). Enables traffic sampling and logging for this * Sample (bit 6). Enables traffic sampling and logging for this
flow specification. flow specification.
Redirect The redirect extended community allows the traffic to be Redirect The redirect extended community allows the traffic to be
redirected to a VRF routing instance that list the specified redirected to a VRF routing instance that list the specified
route-target in its import policy. If several local instances route-target in its import policy. If several local instances
match this criteria, the choice between them is a local matter match this criteria, the choice between them is a local matter
(for example, the instance with the lowest Route Distinguisher (for example, the instance with the lowest Route Distinguisher
value can be elected). value can be elected). This extended community uses the same
encoding as the Route Target extended community [RFC4360]
Traffic Marking The traffic marking extended community instructs a Traffic Marking The traffic marking extended community instructs a
system to modify the DSCP bits of a transiting IP packet to the system to modify the DSCP bits of a transiting IP packet to the
corresponding value. This extended community is encoded as a corresponding value. This extended community is encoded as a
sequence of 5 zero bytes followed by the DSCP value. sequence of 5 zero bytes followed by the DSCP value encoded in the
6 least significant bits of 6th byte.
8. Traffic filtering in RFC2547bis networks 8. Traffic filtering in RFC2547bis networks
Provider-based layer 3 VPN networks, such as the ones using an BGP/ Provider-based layer 3 VPN networks, such as the ones using an BGP/
MPLS IP VPN [RFC4364] control plane, have different traffic filtering MPLS IP VPN [RFC4364] control plane, have different traffic filtering
requirements than internet service providers. requirements than internet service providers.
In these environments, the VPN customer network often has traffic In these environments, the VPN customer network often has traffic
filtering capabilities towards their external network connections filtering capabilities towards their external network connections
(e.g. firewall facing public network connection). Less common is the (e.g. firewall facing public network connection). Less common is the
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The authors would like to thank Yakov Rekhter, Dennis Ferguson, Chris The authors would like to thank Yakov Rekhter, Dennis Ferguson, Chris
Morrow, Charlie Kaufman and David Smith for their comments. Morrow, Charlie Kaufman and David Smith for their comments.
Chaitanya Kodeboyina helped design the flow validation procedure. Chaitanya Kodeboyina helped design the flow validation procedure.
Steven Lin and Jim Washburn ironed out all the details necessary to Steven Lin and Jim Washburn ironed out all the details necessary to
produce a working implementation. produce a working implementation.
13. Normative References 13. Normative References
[IEEE.754.1985]
Institute of Electrical and Electronics Engineers,
"Standard for Binary Floating-Point Arithmetic",
IEEE Standard 754, August 1985.
[RFC0793] Postel, J., "Transmission Control Protocol", STD 7, [RFC0793] Postel, J., "Transmission Control Protocol", STD 7,
RFC 793, September 1981. RFC 793, September 1981.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers", RFC 2474,
December 1998.
[RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
Protocol 4 (BGP-4)", RFC 4271, January 2006. Protocol 4 (BGP-4)", RFC 4271, January 2006.
[RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)",
RFC 4303, December 2005. RFC 4303, December 2005.
[RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended [RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
Communities Attribute", RFC 4360, February 2006. Communities Attribute", RFC 4360, February 2006.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private [RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
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