RTG Working Group A. Clemm
Internet-Draft P. Pillay-Esnault
Intended status: Standards Track U. Chunduri
Expires: January 9, 2020 Futurewei
July 8, 2019
Preferred Path Routing (PPR) OAM and Accounting
draft-cpc-rtgwg-ppr-oam-00
Abstract
This document defines OAM and traffic accounting capabilities for
Preferred Path Routing (PPR) for IS-IS and OSPF protocols.
Specifically, this document specifies OAM capabilities that allow to
assert proper PPR connectivity and to trace PPR path information. In
addition, a set of statistics and operational data to facilitate PPR
traffic accounting on a per-PPR path basis are defined. This
includes a number of Information Elements that extend IPFIX to export
path information, as well as a YANG Data Model to be used in
conjunction with management and control protocols. Collectively the
capabilities defined in this document provide network operators with
the necessary means to ensure proper working of their PPR
deployments.
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 RFC2119 [RFC2119],
RFC8174 [RFC8174] when, and only when they appear in all capitals, as
shown here.
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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Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
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This Internet-Draft will expire on January 9, 2020.
Copyright Notice
Copyright (c) 2019 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
(https://trustee.ietf.org/license-info) in effect on the date of
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carefully, as they describe your rights and restrictions with respect
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Key Words . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Definition and Acronyms . . . . . . . . . . . . . . . . . . . 4
4. PPR Ping and Trace Functionality . . . . . . . . . . . . . . 4
4.1. PPR Trace Functionality in Strict Mode . . . . . . . . . 6
4.2. PPR Trace Functionality in Loose Mode . . . . . . . . . . 7
5. Traffic Accounting through IGP PPR-Attribute Sub-TLVs . . . . 8
6. Path Statistics and IP[F/P]IX . . . . . . . . . . . . . . . . 9
7. A YANG Data Model for PPR Monitoring . . . . . . . . . . . . 11
7.1. Motivation and Overview . . . . . . . . . . . . . . . . . 11
7.2. YANG Data Model . . . . . . . . . . . . . . . . . . . . . 13
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 16
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
9.1. IGP Path Attributes . . . . . . . . . . . . . . . . . . . 16
9.2. IPFIX Information Elements . . . . . . . . . . . . . . . 16
9.3. YANG Data Model . . . . . . . . . . . . . . . . . . . . . 16
10. Security Considerations . . . . . . . . . . . . . . . . . . . 17
10.1. Path Trace and Ping . . . . . . . . . . . . . . . . . . 17
10.2. IGPs and IPFIX . . . . . . . . . . . . . . . . . . . . . 17
10.3. YANG Data Model . . . . . . . . . . . . . . . . . . . . 18
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
11.1. Normative References . . . . . . . . . . . . . . . . . . 18
11.2. Informative References . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21
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1. Introduction
Preferred Path Routing (PPR) allows to route packets along a custom
path on the basis of a path identifier (PPR-ID) as opposed to
individual segments in the packet. Interior Gateway Protocols (IGPs)
nodes compute nexthops based on the path description for the prefix
and take proper forwarding actions for the paths that they are a part
of. PPR may be used with different data planes, e.g. IPv4, IPv6,
MPLS, SRv6. Dissemination and nexthop computation of path
information is described in
[I-D.chunduri-lsr-isis-preferred-path-routing] and
[I-D.chunduri-lsr-ospf-preferred-path-routing].
In order to operate, administer, and maintain PPR deployments,
network operators must be given tools that allow them to ensure that
PPR is working as expected and that allow them to troubleshoot any
potential problems. This includes assessing whether remote
destinations can indeed be reached as intended using a given
preferred path, and to verify path elements along the path being
taken. Traditionally, ping (ICMP echo request on IP networks, LSP
ping in MPLS networks) and traceroute operations are used for those
purposes. In order to facilitate operation of PPR, analogous
capabilities with PPR-specific extensions are useful which are
defined in this document.
In addition, for purposes of traffic accounting and ongoing
operations, it can be very useful to maintain certain PPR statistics.
This allows, for example, to assess times and volume when traffic
over preferred paths is occurring. This document defines new PPR
path attributes as defined in Section 5 and this can be optionally
signaled for the preferred paths selectively to account for the
traffic on every path segment (where critical SLAs are needed).
IPFIX is commonly used to maintain and export flow-specific
information from any node in the network. This document introduces a
number of new IPFIX Information Elements that are useful in
conjunction with PPR.
Some of the same statistics maintained on a per-flow basis may be
useful to maintain not just for the duration of a flow, but for the
lifetime of the path. That information is considered part of regular
management information and subject to specification as part of a YANG
data model.
2. Key Words
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
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14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Definition and Acronyms
o IE: IPFIX Information Element
o IGP: Interior Gateway Protocol
o IPFIX: IP Flow Information eXport
o IS-IS Link State PDU
o PPR: Preferred Path Routing/Route
o PPR-ID: Preferred Path Route Identifier, a data plane identifier
o SRH: Segment Routing Header - IPv6 routing Extension header
o SRv6: Segment Routing with Ipv6 data plane with SRH
o TE: Traffic Engineering
4. PPR Ping and Trace Functionality
Ping and Trace capabilities depend on the underlying data plane being
used for the PPR path. Different mechanisms exist for each of those
data planes. As PPR support does not require any change in the
existing dataplane, for each of those cases, existing ping and trace
core mechanisms continue to work seamlessly without modification:
IPv4 data plane: ICMP [RFC792]
IPv6 data plane: ICMPv6 [RFC4443]
MPLS data plane: LSP Ping [RFC8287]
SRv6 data plane: Mechanism under development
To manage PPR, network operators may require additional information
that is specific to PPR. For example, PPR may be installed by
different IGPs(OSPF/ISIS) and supports two types of paths:
(1) Strict: where all the nodes on the path are specified and the
traffic is forwarded at every single hop to the next node
defined in the path.
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(2) Loose: where not all nodes are described in the path. There are
section(s) of the path that are unspecified and the packets are
forwarded based on the local router forwarding until the next
node in the path description.
The current mechanisms need to be enhanced to carry the PPR specific
mechanism but otherwise it has minimal changes. In this section, a
simple topology is shown in Figure 1 is used to illustrate the
different traces of PPR paths described in the subsequent sub
sections below.
1 __R9___R10__ 1
/ 1 \
R1-------R2 R3------R4
\_____R11____/
2 2
Figure 1. Topology example
PPR paths from topology
PPR-ID: (strict) -> R1, R2, R3, R11, R4
PPR-ID: (Loose) -> R1, R2, R3, R4
The section between R2-R3 is loose.
The best path is via R9 and 10. Path is R1, R2, (R9, R10), R3, R4
Node Node IPaddr SPF Cost to R3
R1 1.1.1.1
R2 2.2.2.2 costs via R9+R10=3, via R11=4
R3 3.3.3.3
R4 4.4.4.4
R9 9.9.9.9
R10 10.10.10.10
R11 11.11.11.11
The classic ping to a destination relying on the forwarding path
works seamlessly as the PPR path is installed via IGPs. The PPR-ID
is the same as the destination address/label in different dataplanes,
therefore the existing ping mechanism remains unchanged in a network
supporting PPR.
However, the traceroute output should display more PPR specific
information such as whether or not the path from a node is loose or
strict, or the source of the protocol that installed a PPR-ID or the
dataplane information. In order to support PPR-specific trace
information, a few additional capabilities are needed.
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A PPR Trace is initiated from a node, using the PPR-ID as a
parameter. The trace will then traverse the PPR path of the
specified PPR-ID. In addition to the information that would be
returned with a regular trace, PPR-specific information is returned
from PPR nodes that are encountered along the path. For each PPR
node, the following information is returned:
(1) Node Information: Provides the loopback identifier of the node
(TBD).
(2) Loose-or-strict-or-none: Indicates whether the path from that
node is loose or strict, or whether the node is PPR-capable but
not one of the nodes designated in the path. The latter can be
the case for transit nodes on a loose segment of the path.
(3) PPR-Origin Protocol: Indicates the protocol that installed the
PPR-ID in the FIB.
(4) PPR-ID: Indicates the PPR-ID of the packet as received. This is
needed in case of a loose path, leading to encapsulated PPR-ID,
described further in Section 4.2.
These PPR specific information will be carried in ICMP data. These
extensions are TBD for the various dataplanes.
4.1. PPR Trace Functionality in Strict Mode
The PPR strict mode indicates the PPR path on a hop by hop basis. As
the PPR-ID represents a strict path to be followed, the ingress node
should increment the TTL for the PPR-ID until all the egress node has
returned all individual intermediate segments completely traced.
The PPR specific enhancements additional information are returned as
part of trace information. The strict path to be trace is PPR-
ID=4.4.4.5 represents the path (R1, R2, R11, R3, R4). An example of
the output for traceroute for PPR-IS in IPV4 dataplane is given
below:
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>traceroute 4.4.4.5
traceroute to 4.4.4.5 (192.4.4.5), 30 hops max, 40 byte packets
1 1.1.1.1 (192.1.1.1) 6.819 ms 1.370 ms 1.281 ms
PPR: ID:4.4.4.5 Mode=Strict Origin=IS-IS
2 2.2.2.2 (192.1.1.2) 4.437 ms 1.987 ms 2.335 ms
PPR: ID:4.4.4.5 Mode=Strict Origin=IS-IS
3 11.11.11.11 (192.11.11.11) 9.830 ms 11.696 ms 5.478 ms
PPR: ID:4.4.4.5 Mode=Strict Origin=IS-IS
4 3.3.3.3 (192.3.3.3) 9.448 ms 5.096 ms 7.518 ms
PPR: ID:4.4.4.5 Mode=Strict Origin=IS-IS
5 4.4.4.4 (192.3.3.4) 9.448 ms 5.096 ms 7.518 ms
PPR: ID:4.4.4.5 Mode=Strict Origin=IS-IS
Figure 2 Enhanced traceroute Output example
The output for IPv6 and MPLS traceroute should be augmented to
display the PPR-ID specific parameters as shown above.
4.2. PPR Trace Functionality in Loose Mode
The PPR loose path functionality allows greater flexibility by
letting the IGP calculate the best path on a loose section of the
path described for PPR-ID. The traditional traceroute requires
additional enhancement for the PPR trace to perform correctly . Per
Figure 1, the loose path example is R1, R2,(R9, R10), R3, R4 where ()
represents the loose section of the path. An example of the output
for traceroute for PPR-IS in IPV4 dataplane is given below:
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>traceroute 4.4.4.5
traceroute to 4.4.4.5 (192.4.4.5), 30 hops max, 40 byte packets
1 1.1.1.1 (192.1.1.1) 6.819 ms 1.370 ms 1.281 ms
PPR: ID:4.4.4.5 Mode=Strict Origin=OSPF
2 2.2.2.2 (192.1.1.2) 4.437 ms 1.987 ms 2.335 ms
PPR: ID:4.4.4.5 Mode=Loose Origin=OSPF Multipaths=0
1 9.9.9.9 (192.9.9.9) 9.830 ms 11.696 ms 5.478 ms
PPR: ID:4.4.4.5 Mode=None Origin=OSPF
2 10.10.10.10 (192.9.9.10) 4.230 ms 4.633 ms 5.789 ms
PPR: ID:4.4.4.5 Mode=None Origin=OSPF
3 3.3.3.3 (192.3.3.3) 9.448 ms 5.096 ms 7.518 ms
PPR: ID:4.4.4.5 Mode=Strict Origin =OSPF
4 4.4.4.4 (192.3.3.4) 9.448 ms 5.096 ms 7.518 ms
PPR: ID:4.4.4.5 Mode=Strict Origin=OSPF
Figure 3 Enhanced traceroute Output example
The output for IPv6 and MPLS traceroute should be augmented to
display the PPR-ID, Mode and Origin.
As the loose path functionality does not preclude the presence of
equal cost multiple paths (ECMPs), the well documented limitations
and solutions for classic traceroute applies here as well. For
operational purposes, it might be of value to list all the
multipaths. To acheive this the node just before the loose section
MAY initiate a recursive traceroute to aggregate that information and
send it with their ICMP Echo Reply message.
5. Traffic Accounting through IGP PPR-Attribute Sub-TLVs
Traffic for certain PPRs may have more stringent requirement w.r.t
accounting for critical SLAs (e.g. 5G non-eMBB slice) and should
account for any link/node failures along the path. Presence of
"Packet Traffic Accounting" and "Traffic Statistics" Sub-TLVs below
in IGP PPR-TLV instructs all the respective nodes along the path to
provision the hardware and to account for the respective traffic
statistics. Traffic accounting should happen, when the actual data
traffic hits for the PPR-ID in the forwarding plane. This capability
allows more granular and dynamic enablement of traffic statistics for
only certain PPRs as needed.
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As instruction for creating and deleting the traffic accounting for
PPRs happen through IGP message processing, respective IGP's control
plane security (Section 10) options are applicable to the PPR-TLV and
Sub-TLVs thereof.
PPR-Attribute Sub-TLVs describe the attributes of that particular
path. The following path attribute Sub-TLVs are defined for
respective IGP PPR-TLV [I-D.chunduri-lsr-isis-preferred-path-routing]
and [I-D.chunduri-lsr-ospf-preferred-path-routing].
o Type 10 (Suggested Value - IANA TBD): Packet Traffic accounting
Sub-TLV. Length 0 and has no value field. Specifies to create a
counter to count number of packets forwarded on this PPR-ID on
each node in the path description.
o Type 11 (Suggested Value - IANA TBD): Traffic statistics in Bytes
Sub-TLV. Length 0 and has no value field. Specifies to create a
counter to count number of bytes forwarded on this PPR-ID
specified in the network header (e.g. IPv4, IPv6) on each node in
the path description.
How the accumulated traffic accounting information is distributed to
a central entity is out of scope of this document. One can use any
method (e.g. RESTCONF, Yang PUSH, gRPC) to extract the PPR-ID
traffic accounting information from various nodes along the path.
6. Path Statistics and IP[F/P]IX
Network providers will appreciate the ability to collect certain
statistics about PPR path usage, including how much traffic a PPR
path carries and at what times from any node in the network. Such
statistics can be useful to account for the degree of usage of a path
and provide additional operational insights, including (for example)
usage patterns and trending information.
One mechanism that is traditionally used to collect traffic
statistics is IPFIX (IP Flow Information eXport [RFC7011]. IPFIX
supports a very rich set of Information Elements containing various
statistics, far more in fact than will be required for PPR path
statistics. However, those statistics are collected only a per-flow
basis.
In order to be able to collect statistics on a per-path basis, a set
of new IPFIX Information Elements need to be defined that allow to
capture a PPR-ID. In addition, these new IPFIX Information Elements
need to be able to serve as a flow key. This allows separate IPFIX
cache entries to be created on a per-path basis, and to export the
corresponding records as IPFIX records. Of course, the records
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exported do not refer to flows but to paths - IPFIX thus becomes de-
facto extended to become IPPIX - IP Path Information eXport.
Flow records that have a PPR-ID as flow key SHALL be terminated and
exported in the following events and/or per configurable policy:
o When no packet has not been observed on a path for a time interval
defined by a flow inactivity timer.
o When the flow has reached a certain age, defined by a flow
termination timer.
A flow record for path is created when a packet on a path is detected
and no flow entry for that PPR-ID exists. I.e., flow records are not
created and maintained for every PPR-ID that is known to the Network
Element, only to PPR-IDs that are "active".
The following new IPFIX Information Elements need to be added:
o pprid-ipv4, with ipv4address as abstract data type.
o pprid-ipv6, with ipv6address as abstract data type.
o pprid-mpls, with unsigned32 as abstract data type.
o pprid-srv6, which is for further study.
Each of those fields need to be able to be supported as a flow key
field.
The following statistics, as represented through corresponding
Information Elements, will be of particular interest to export as
part of IPFIX records with a PPR-ID as flow key:
o IE 1: octetDeltaCount - the number of octets on this path
o IE 2: packetDeltaCount - the number of incoming packets on this
path
o IE 3: deltaFlowCount - the number of original flows routed via
this path
o IE 21: flowEndSysUpTime - the relative time stamp of the last
packet of the path flow (i.e. end of the observation period that
is covered by the record)
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o IE 22: flowStartSysUpTime - the relative time stamp of the first
packet of the path flow (i.e. beginning of the observation period
that is covered by the record)
o IE 132: droppedOctetDeltaCount - the number of octets of the path
flow that were dropped by the node (during the observation period
covered by the record).
o IE 133: droppedPacketDeltaCount - the number of packets of the
path flow that were dropped by the node (during the observation
period covered by the record).
Because a path's packets traverse every hop on the path, the observed
path statistics are expected to generally be the same on every node
across the path. Network providers may therefore choose to configure
IPFIX path information export only on certain routers, for example at
the network edge. That said, in certain circumstances it may make
sense to export statistics from multiple nodes on a path and compare
records for any discrepancies in order to diagnose or isolate
operational anomalies (such as occurrence of packet loss).
7. A YANG Data Model for PPR Monitoring
7.1. Motivation and Overview
In addition to exporting path flow statistics, network providers need
to be able to retrieve operational information about PPR paths as a
whole. This includes information about when a path was created, how
it came into being, and statistics maintained over the entire
lifetime of the path (i.e. since its creation). For this purpose, a
YANG Data Model for PPR Monitoring is defined, "ppr-statistics". The
model is depicted in the following tree diagram. The tree diagram
follows the notation defined in [RFC8340]
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module: ietf-ppr-statistics
+--ro ppr-stats
+--ro num-pprs? uint32
+--ro ppr* [ppr-id]
+--ro ppr-id ppr-id
+--ro ppr-creation-time? yang:date-and-time
+--ro loose-or-strict? ppr-path-type
+--ro ppr-origin? ppr-origin-proto
+--ro ppr-packets? uint64
+--ro ppr-dropped-packets? uint64
+--ro ppr-octets? uint64
+--ro ppr-active-flows? uint32
Figure 1: Tree diagram for establish-subscription-datastore-error-
info
The data model contains the following:
o num-pprs: indicates the number of currently active PPRs on the
node.
o ppr: the list of PPRs configured on the node, indexed by ppr-id,
with the following entries:
* ppr-creation-time: indicates the time the PPR came into being.
* loose-or-strict: indicates whether the PPR is loose or strict.
* ppr-origin: indicates the way in which the PPR came into being,
i.e. through which method or protocol it was created.
* ppr-packets: the number of packets that have forwarded on that
path. (Wrapping around to 0 when the maximum is reached, per
modulo semantics).
* ppr-dropped packets: the number of packets on that path that
have been dropped by this node. (Wrapping around to 0 when the
maximum is reached, per modulo semantics).
* ppr-octets: the number of octets that have been forwarded on
that path. (Wrapping aound to 0 when the maxium is reached,
per modulo semantics).
* ppr-active-flows: The number of distinct flows that are
currently active on that path.
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7.2. YANG Data Model
<CODE BEGINS> file "ietf-ppr-statistics@2019-07-08.yang"
module ietf-ppr-statistics {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-ppr-statistics";
prefix pprs;
import ietf-yang-types {
prefix yang;
}
import ietf-inet-types {
prefix inet;
}
organization "IETF";
contact
"WG Web: <http://tools.ietf.org/wg/rtgwg/>
WG List: <mailto:rtgwg@ietf.org>
Author: Alexander Clemm
<mailto:ludwig@clemm.org>
Author: Padma Pillay-Esnault
<mailto:padma@futurewei.com>
Author: Uma Chunduri
<mailto:uchundur@futurewei.com>";
description
"The YANG data model defines a set of statistics to be used for
managing PPR.";
revision 2019-07-08 {
description
"Initial revision";
reference
"RFC XXXX: Preferred Path Routing (PPR) OAM and Accounting";
}
typedef ppr-id {
type union {
type inet:ipv4-address;
type inet:ipv6-address;
type string {
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length "4..32";
}
}
description
"Identifies a PPR. Depending on the type of PPR, a different
format is used.";
}
typedef ppr-origin-proto {
type string;
description
"Identifies the source of the PPR, i.e. how the PPR came into
being. Different values are TBD and the type itself is
subject to change.";
}
typedef ppr-path-type {
type enumeration {
enum loose {
description "Path type is loose";
}
enum strict {
description "Path type is strict";
}
}
description
"The type of PPR path - loose or strict.";
}
container ppr-stats {
config false;
description
"Top-level container for PPR statistics.";
leaf num-pprs {
type uint32;
description
"The number of currently active PPRs on the node.";
}
list ppr {
key "ppr-id";
description
"The list of currently active PPRs on the node.";
leaf ppr-id {
type ppr-id;
description
"The identifier of the PPR.";
}
leaf ppr-creation-time {
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type yang:date-and-time;
description
"The precise time at which the PPR was created on the
node.";
}
leaf loose-or-strict {
type ppr-path-type;
description
"An indication whether the PPR is loose or strict.";
}
leaf ppr-origin {
type ppr-origin-proto;
description
"The way in which the PPR came into being, i.e. through
which method or protocol it was created.";
}
leaf ppr-packets {
type uint64;
description
"The number of packets that have forwarded on that path.
(Modulo semantics apply, i.e. the value of the leaf wraps
around to 0 when the maximum uint64 is reached.)";
}
leaf ppr-dropped-packets {
type uint64;
description
"The number of packets on that path that have been dropped
by this node. (Modulo semantics apply, i.e. the value of
the leaf wraps around to 0 when the maximum uint64 is
reached.)";
}
leaf ppr-octets {
type uint64;
description
"The number of octets that have been forwarded on that
path. (Modulo semantics apply, i.e. the value of the
leaf wraps around to 0 when the maximum uint64 is
reached.)";
}
leaf ppr-active-flows {
type uint32;
description
"The number of distinct flows that are currently active
on that path.";
}
}
}
}
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<CODE ENDS>
8. Acknowledgements
tbd
9. IANA Considerations
9.1. IGP Path Attributes
This document requests the following new code points in IANA PPR
Attributes TLV code-point registry for IS-IS, OSPFv2 and OSPFv3
protocols. IS-IS PPR Attributes are defined in
[I-D.chunduri-lsr-isis-preferred-path-routing] and OSPF PPR
attributes are defined in
[I-D.chunduri-lsr-isis-preferred-path-routing].
Sub-TLV # Sub-TLV Name
--------- ---------------------------------------------------------
10 Packet Traffic Accounting (Section 5)
11 Traffic Statistics (Section 5)
add capability for loose traceroute support.
9.2. IPFIX Information Elements
IANA is requested to add the following entries to the IPFIX
Information Elements Registry:
o pprid-ipv4, with ipv4address as abstract data type.
o pprid-ipv6, with ipv6address as abstract data type.
o pprid-mpls, with unsigned32 as abstract data type.
o pprid-srv6, whose abstract data type is for further study.
9.3. YANG Data Model
This document registers the following namespace URI in the "IETF XML
Registry" [RFC3688]:
URI: urn:ietf:params:xml:ns:yang:ietf-ppr-statistics
Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace.
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This document registers the following YANG module in the "YANG Module
Names" registry [RFC6020]:
Name: ietf-ppr-statistics
Namespace: urn:ietf:params:xml:ns:yang:ietf-ppr-statistics
Prefix: pprs
Reference: draft-cpc-rtgwg-ppr-oam-XX.txt (RFC form)
10. Security Considerations
10.1. Path Trace and Ping
The ability to perform path traces and pings could be used by an
attacker to discover details of a network. In addition, excessive
amounts of traces and pings could be used by an attacker to try and
exhaust network resources. Network providers therefore need to
secure the ability to invoke trace and ping operations, requiring
proper auhorization and authentication. Likewise, trace or ping
requests originating from an untrusted source from outside the
network edge should be dropped at the ingress edge.
10.2. IGPs and IPFIX
Security concerns for IS-IS are addressed in [RFC5304] and [RFC5310].
Further security analysis for IS-IS protocol is done in [RFC7645]
with detailed analysis of various security threats and why [RFC5304]
should not be used in the deployments. Advertisement of the
additional information defined in this document introduces no new
security concerns in IS-IS protocol. However as this extension is
related to SR-MPLS and SRH data planes as defined in [I-D.ietf-
spring-segment-routing], those particular data plane security
considerations does apply here.
Existing security extensions for OSPF protocol are described in
[RFC2328] and [RFC7684] apply to the extensions specified in this
document. While OSPF is under a single administrative domain, there
can be deployments where potential attackers have access to one or
more networks in the OSPF routing domain. In these deployments,
stronger authentication mechanisms such as those specified in
[RFC7474] SHOULD be used.
This document also describes IPFX extensions that allow it to be used
as a mechanism for IP Path Information Export. IPFIX security
considerations apply, which are detailed in [RFC7011] section 11.
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10.3. YANG Data Model
The YANG module specified in this document defines a schema for data
that is designed to be accessed via network management protocols such
as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer
is the secure transport layer, and the mandatory-to-implement secure
transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer
is HTTPS, and the mandatory-to-implement secure transport is TLS
[RFC8446].
The Network Configuration Access Control Model (NACM) [RFC8341]
provides the means to restrict access for particular NETCONF or
RESTCONF users to a preconfigured subset of all available NETCONF or
RESTCONF protocol operations and content.
Some of the readable data nodes in this YANG module may be considered
sensitive or vulnerable in some network environments. It is thus
important to control read access (e.g., via get, get-config, or
notification) to these data nodes. The readable data nodes are
defined under the container "ppr-stats". The sensitivity/
vulnerability concerns providing an unauthorized attacker with
internals about the network, specifically exposure of PPR IDs that
are installed on a network node and insight about the network traffic
that occurs over these nodes.
11. References
11.1. Normative References
[I-D.chunduri-lsr-isis-preferred-path-routing]
Chunduri, U., Li, R., White, R., Tantsura, J., Contreras,
L., and Y. Qu, "Preferred Path Routing (PPR) in IS-IS",
draft-chunduri-lsr-isis-preferred-path-routing-03 (work in
progress), May 2019.
[I-D.chunduri-lsr-ospf-preferred-path-routing]
Chunduri, U., Qu, Y., White, R., Tantsura, J., and L.
Contreras, "Preferred Path Routing (PPR) in OSPF", draft-
chunduri-lsr-ospf-preferred-path-routing-03 (work in
progress), May 2019.
[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>.
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[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet
Control Message Protocol (ICMPv6) for the Internet
Protocol Version 6 (IPv6) Specification", STD 89,
RFC 4443, DOI 10.17487/RFC4443, March 2006,
<https://www.rfc-editor.org/info/rfc4443>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/info/rfc6020>.
[RFC7011] Claise, B., Ed., Trammell, B., Ed., and P. Aitken,
"Specification of the IP Flow Information Export (IPFIX)
Protocol for the Exchange of Flow Information", STD 77,
RFC 7011, DOI 10.17487/RFC7011, September 2013,
<https://www.rfc-editor.org/info/rfc7011>.
[RFC8029] Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N.,
Aldrin, S., and M. Chen, "Detecting Multiprotocol Label
Switched (MPLS) Data-Plane Failures", RFC 8029,
DOI 10.17487/RFC8029, March 2017,
<https://www.rfc-editor.org/info/rfc8029>.
[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>.
[RFC8287] Kumar, N., Ed., Pignataro, C., Ed., Swallow, G., Akiya,
N., Kini, S., and M. Chen, "Label Switched Path (LSP)
Ping/Traceroute for Segment Routing (SR) IGP-Prefix and
IGP-Adjacency Segment Identifiers (SIDs) with MPLS Data
Planes", RFC 8287, DOI 10.17487/RFC8287, December 2017,
<https://www.rfc-editor.org/info/rfc8287>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/info/rfc8340>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/info/rfc8341>.
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11.2. Informative References
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328,
DOI 10.17487/RFC2328, April 1998,
<https://www.rfc-editor.org/info/rfc2328>.
[RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic
Authentication", RFC 5304, DOI 10.17487/RFC5304, October
2008, <https://www.rfc-editor.org/info/rfc5304>.
[RFC5310] Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,
and M. Fanto, "IS-IS Generic Cryptographic
Authentication", RFC 5310, DOI 10.17487/RFC5310, February
2009, <https://www.rfc-editor.org/info/rfc5310>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
<https://www.rfc-editor.org/info/rfc6242>.
[RFC7474] Bhatia, M., Hartman, S., Zhang, D., and A. Lindem, Ed.,
"Security Extension for OSPFv2 When Using Manual Key
Management", RFC 7474, DOI 10.17487/RFC7474, April 2015,
<https://www.rfc-editor.org/info/rfc7474>.
[RFC7645] Chunduri, U., Tian, A., and W. Lu, "The Keying and
Authentication for Routing Protocol (KARP) IS-IS Security
Analysis", RFC 7645, DOI 10.17487/RFC7645, September 2015,
<https://www.rfc-editor.org/info/rfc7645>.
[RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W.,
Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute
Advertisement", RFC 7684, DOI 10.17487/RFC7684, November
2015, <https://www.rfc-editor.org/info/rfc7684>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
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Authors' Addresses
Alexander Clemm
Futurewei
2330 Central Expressway
Santa Clara, CA 95050
USA
Email: ludwig@clemm.org
Padma Pillay-Esnault
Futurewei
2330 Central Expressway
Santa Clara, CA 95050
USA
Email: padma@futurewei.com
Uma Chunduri
Futurewei
2330 Central Expressway
Santa Clara, CA 95050
USA
Email: umac.ietf@gmail.com
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