draft-ietf-bmwg-fib-term-03.txt   draft-ietf-bmwg-fib-term-04.txt 
Benchmarking Methodology Working Group G. Trotter Benchmarking Methodology Working Group G. Trotter
Internet Draft Agilent Technologies Internet Draft Agilent Technologies
Document: draft-ietf-bmwg-fib-term-03.txt September 2001 Document: draft-ietf-bmwg-fib-term-04.txt October 2001
Category: Informational Category: Informational
Terminology for Forwarding Information Base (FIB) based Router Terminology for Forwarding Information Base (FIB) based Router
Performance Performance
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026 [1]. all provisions of Section 10 of RFC2026 [1].
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4. Definition Format...............................................3 4. Definition Format...............................................3
5. Definitions - parameters........................................3 5. Definitions - parameters........................................3
5.1 Network Prefix.................................................3 5.1 Network Prefix.................................................3
5.2 Network Prefix Length..........................................4 5.2 Network Prefix Length..........................................4
5.3 Forwarding Information Base (FIB)..............................4 5.3 Forwarding Information Base (FIB)..............................4
5.4 Forwarding Information Base Entry..............................5 5.4 Forwarding Information Base Entry..............................5
5.5 Forwarding Information Base Size...............................5 5.5 Forwarding Information Base Size...............................5
5.6 Longest Length Prefix Match Algorithm..........................6 5.6 Longest Length Prefix Match Algorithm..........................6
5.7 Forwarding Information Base Prefix Distribution................6 5.7 Forwarding Information Base Prefix Distribution................6
5.8 Per-Interface or Per-Card Forwarding Information Base..........7 5.8 Per-Interface or Per-Card Forwarding Information Base..........7
Terminology for FIB based Router Performance Sept., 2001 Terminology for FIB based Router Performance Oct., 2001
5.9 Per-Interface Forwarding Information Base Cache................8 5.9 Per-Interface Forwarding Information Base Cache................8
5.10 Route Aggregation.............................................9 5.10 Route Aggregation.............................................8
6. Definitions - metrics...........................................9 6. Definitions - metrics...........................................9
6.1 Maximum Forwarding Information Base Size.......................9 6.1 Maximum Forwarding Information Base Size.......................9
6.2 Forwarding Information Base Learning Time.....................10 6.2 Forwarding Information Base Learning Time.....................10
6.3 Forwarding Information Base-dependent Throughput..............11 6.3 Forwarding Information Base-dependent Throughput..............11
6.4 Forwarding Information Base-dependent Latency.................11 6.4 Forwarding Information Base-dependent Latency.................11
6.5 Forwarding Information Base-dependent Frame Loss Rate.........11 6.5 Forwarding Information Base-dependent Frame Loss Rate.........11
7. Security Considerations........................................12 7. Security Considerations........................................12
8. References.....................................................12 8. References.....................................................12
9. Acknowledgments................................................12 9. Acknowledgments................................................12
10. Author's Addresses............................................12 10. Author's Addresses............................................12
1. Introduction 1. Introduction
This document defines terms that are to be used in a methodology This document defines terms that are to be used in a methodology
that determines the IP packet forwarding performance of IP routers that determines the IP packet forwarding performance of IP routers
as a function of the forwarding information base installed within as a function of the forwarding information base installed within
the router. the router.
This document is restricted to IPv4 routers.
The objective of this methodology is to evaluate the performance The objective of this methodology is to evaluate the performance
levels of IP routers as forwarding information bases continue to levels of IP routers as forwarding information bases continue to
grow in size and complexity of structure. grow in size and complexity of structure.
This methodology utilizes the packet forwarding performance This methodology utilizes the packet forwarding performance
measurements described in [2]; reference will also be made to the measurements described in [2]; reference will also be made to the
associated terminology document [3] for these terms. associated terminology document [3] for these terms.
2. Overview 2. Overview
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the router. Tests may need to be performed up to the maximum FIB the router. Tests may need to be performed up to the maximum FIB
size (6.1). size (6.1).
When configuring the router for these measurements, the routes need When configuring the router for these measurements, the routes need
to be manually entered into the router, or advertised via a routing to be manually entered into the router, or advertised via a routing
protocol. It may take some period of time (the FIB learning time protocol. It may take some period of time (the FIB learning time
(6.2)) before the router learns all the routes. (6.2)) before the router learns all the routes.
When routes are advertised into the router, the routes should be When routes are advertised into the router, the routes should be
advertised in such a way so that route aggregation (5.10) does not advertised in such a way so that route aggregation (5.10) does not
Terminology for FIB based Router Performance Sept., 2001
occur. Also, the effect of a per-interface FIB cache (5.9) needs to occur. Also, the effect of a per-interface FIB cache (5.9) needs to
be taken into account. be taken into account.
Terminology for FIB based Router Performance Oct., 2001
3. Existing Definitions 3. Existing Definitions
[3] should be consulted before attempting to make use of this [3] should be consulted before attempting to make use of this
document. [2] contains discussions of a number of terms relevant to document. [2] contains discussions of a number of terms relevant to
the benchmarking of network interconnect devices and should also be the benchmarking of network interconnect devices and should also be
consulted. consulted.
4. Definition Format 4. Definition Format
The definition format is the equivalent to that defined in [3], and The definition format is the equivalent to that defined in [3], and
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Definition: Definition:
"A network prefix is . . . a contiguous set of bits at the "A network prefix is . . . a contiguous set of bits at the
more significant end of the address that defines a set of more significant end of the address that defines a set of
systems; host numbers select among those systems." systems; host numbers select among those systems."
(This definition is taken directly from section 2.2.5, (This definition is taken directly from section 2.2.5,
"Addressing Architecture", in [4].) "Addressing Architecture", in [4].)
Discussion: Discussion:
Terminology for FIB based Router Performance Sept., 2001
In the CIDR context, the network prefix is the network In the CIDR context, the network prefix is the network
component of an IP address. A common alternative to using a component of an IP address. A common alternative to using a
bitwise mask to communicate this component is the use of bitwise mask to communicate this component is the use of
Terminology for FIB based Router Performance Oct., 2001
"slash (/) notation." Slash notation binds the notion of "slash (/) notation." Slash notation binds the notion of
network prefix length (see 5.2) in bits to an IP address. network prefix length (see 5.2) in bits to an IP address.
E.g., 141.184.128.0/17 indicates the network component of E.g., 141.184.128.0/17 indicates the network component of
this IPv4 address is 17 bits wide. this IPv4 address is 17 bits wide.
Measurement units: Measurement units:
<n/a> <n/a>
Issues: Issues:
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Definition: Definition:
As according to the definition in [4]: As according to the definition in [4]:
"The table containing the information necessary to forward IP "The table containing the information necessary to forward IP
Datagrams, in this document, is called the Forwarding Datagrams, in this document, is called the Forwarding
Information Base. At minimum, this contains the interface Information Base. At minimum, this contains the interface
identifier and next hop information for each reachable identifier and next hop information for each reachable
destination network prefix." destination network prefix."
Discussion: Discussion:
Terminology for FIB based Router Performance Sept., 2001
The forwarding information base describes a database indexing The forwarding information base describes a database indexing
network prefixes versus router port identifiers. network prefixes versus router port identifiers.
Terminology for FIB based Router Performance Oct., 2001
A forwarding information base consists of [FIB size (6.1)] A forwarding information base consists of [FIB size (6.1)]
FIB entries (5.4). FIB entries (5.4).
The forwarding information base is distinct from the "routing The forwarding information base is distinct from the "routing
table" (or, the Routing Information Base), which holds all table" (or, the Routing Information Base), which holds all
routing information received from routing peers. routing information received from routing peers.
The forwarding information base contains unique paths only The forwarding information base contains unique paths only
(i.e. does not contain secondary paths). (i.e. does not contain secondary paths).
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See Also: See Also:
forwarding information base (5.3) forwarding information base (5.3)
forwarding information base size (5.5) forwarding information base size (5.5)
forwarding information base prefix distribution (5.6) forwarding information base prefix distribution (5.6)
maximum forwarding information base size (6.1) maximum forwarding information base size (6.1)
5.5 Forwarding Information Base Size 5.5 Forwarding Information Base Size
Definition: Definition:
Terminology for FIB based Router Performance Sept., 2001
Refers to the number of forwarding information base entries Refers to the number of forwarding information base entries
within a forwarding information base. within a forwarding information base.
Discussion: Discussion:
Terminology for FIB based Router Performance Oct., 2001
The number of entries within a forwarding information base is The number of entries within a forwarding information base is
one of the key elements that may influence the forwarding one of the key elements that may influence the forwarding
performance of a router. Generally, the more entries within performance of a router. Generally, the more entries within
the forwarding information base, the longer it could take to the forwarding information base, the longer it could take to
find the longest matching network prefix within the find the longest matching network prefix within the
forwarding information base. forwarding information base.
Measurement units: Measurement units:
Number of routes Number of routes
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forwarding information base. forwarding information base.
Discussion: Discussion:
Network prefixes within the forwarding information base could Network prefixes within the forwarding information base could
be all of a single network prefix length, but, more be all of a single network prefix length, but, more
realistically, the network prefix lengths will be distributed realistically, the network prefix lengths will be distributed
across some range. across some range.
Individual performance measurements will be made against FIBs Individual performance measurements will be made against FIBs
populated with the same network prefix length, as well as populated with the same network prefix length, as well as
Terminology for FIB based Router Performance Sept., 2001
against FIBs with some distribution of network prefix against FIBs with some distribution of network prefix
lengths. lengths.
Terminology for FIB based Router Performance Oct., 2001
The distribution of network prefix lengths may have an impact The distribution of network prefix lengths may have an impact
on the forwarding performance of a router. The longer the on the forwarding performance of a router. The longer the
network prefix length, the longer it will take for a router network prefix length, the longer it will take for a router
to perform the longest length prefix match algorithm, and to perform the longest length prefix match algorithm, and
potentially the lower the performance of the router. potentially the lower the performance of the router.
Measurement units: Measurement units:
The forwarding information base prefix distribution is The forwarding information base prefix distribution is
expressed by a list of network prefix lengths and the expressed by a list of network prefix lengths and the
percentage of entries within the forwarding information base percentage of entries within the forwarding information base
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router. By doing this, destination address / network prefix router. By doing this, destination address / network prefix
lookups can be performed on the interface or card, unloading lookups can be performed on the interface or card, unloading
a router's CPU. a router's CPU.
Measurement units: Measurement units:
<n/a> <n/a>
Issues: Issues:
See Also: See Also:
Terminology for FIB based Router Performance Sept., 2001
forwarding information base (5.3) forwarding information base (5.3)
per-interface forwarding information base cache (5.9) per-interface forwarding information base cache (5.9)
Terminology for FIB based Router Performance Oct., 2001
5.9 Per-Interface Forwarding Information Base Cache 5.9 Per-Interface Forwarding Information Base Cache
Definition: Definition:
A subset of a forwarding information base, installed on a A subset of a forwarding information base, installed on a
router's interface card to speed the destination address / router's interface card to speed the destination address /
network prefix lookup process. network prefix lookup process.
Discussion: Discussion:
Prior to installing a complete copy of the forwarding Prior to installing a complete copy of the forwarding
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forwarding performance of the router. forwarding performance of the router.
Measurement units: Measurement units:
<n/a> <n/a>
Issues: Issues:
See Also: See Also:
forwarding information base (5.3) forwarding information base (5.3)
per-interface forwarding information base (5.8) per-interface forwarding information base (5.8)
Terminology for FIB based Router Performance Sept., 2001
5.10 Route Aggregation 5.10 Route Aggregation
Definition: Definition:
Terminology for FIB based Router Performance Oct., 2001
The ability of a router to collapse many forwarding The ability of a router to collapse many forwarding
information base entries into a single entry. information base entries into a single entry.
Discussion: Discussion:
A router may aggregate routes in a forwarding information A router may aggregate routes in a forwarding information
base into a single entry to conserve space. base into a single entry to conserve space.
When advertising routes into a router to perform benchmarking When advertising routes into a router to perform benchmarking
tests as a function of the forwarding information base tests as a function of the forwarding information base
installed within the router, it is necessary to ensure that a installed within the router, it is necessary to ensure that a
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6.1 Maximum Forwarding Information Base Size 6.1 Maximum Forwarding Information Base Size
Definition: Definition:
The maximum number of forwarding information base entries The maximum number of forwarding information base entries
that can be supported within the forwarding information base. that can be supported within the forwarding information base.
The Maximum Forwarding Information Base Size is the size over The Maximum Forwarding Information Base Size is the size over
which all entries can and are used to forward traffic. which all entries can and are used to forward traffic.
Discussion: Discussion:
Terminology for FIB based Router Performance Sept., 2001
It is useful to know the maximum forwarding information base It is useful to know the maximum forwarding information base
size for a router as it will be an indicator of the ability size for a router as it will be an indicator of the ability
of the router to function within the given application space, of the router to function within the given application space,
Terminology for FIB based Router Performance Oct., 2001
and whether the router will be able to handle projected and whether the router will be able to handle projected
network growth. network growth.
As a benchmarking value, it is necessary to discover this As a benchmarking value, it is necessary to discover this
value so that performance measurements can be made up to the value so that performance measurements can be made up to the
maximum possible forwarding information base size. maximum possible forwarding information base size.
Measurement units: Measurement units:
Number of routes Number of routes
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When performing benchmarking tests that take the forwarding When performing benchmarking tests that take the forwarding
information base into account, time must be allocated for the information base into account, time must be allocated for the
router to process the routing information and to install the router to process the routing information and to install the
complete forwarding information base within itself, before complete forwarding information base within itself, before
performance measurements are made. performance measurements are made.
Measurement units: Measurement units:
Prefixes per second. Prefixes per second.
Terminology for FIB based Router Performance Sept., 2001
Issues: Issues:
See Also: See Also:
Terminology for FIB based Router Performance Oct., 2001
forwarding information base (5.3) forwarding information base (5.3)
6.3 Forwarding Information Base-dependent Throughput 6.3 Forwarding Information Base-dependent Throughput
Definition: Definition:
Throughput, as defined in [3], used in a context where the Throughput, as defined in [3], used in a context where the
forwarding information base influences the throughput. forwarding information base influences the throughput.
Discussion: Discussion:
This definition for FIB-dependent throughput is added to This definition for FIB-dependent throughput is added to
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forwarding information base-dependent throughput (6.3) forwarding information base-dependent throughput (6.3)
forwarding information base-dependent frame loss rate (6.5) forwarding information base-dependent frame loss rate (6.5)
6.5 Forwarding Information Base-dependent Frame Loss Rate 6.5 Forwarding Information Base-dependent Frame Loss Rate
Definition: Definition:
Frame Loss Rate, as defined in [3], used in a context where Frame Loss Rate, as defined in [3], used in a context where
the forwarding information base influences the throughput. the forwarding information base influences the throughput.
Discussion: Discussion:
Terminology for FIB based Router Performance Sept., 2001
This definition for FIB-dependent frame loss rate is added to This definition for FIB-dependent frame loss rate is added to
distinguish the context of this measurement from that defined distinguish the context of this measurement from that defined
in [3]. in [3].
Terminology for FIB based Router Performance Oct., 2001
Measurement units: Measurement units:
See [3]. See [3].
Issues: Issues:
See Also: See Also:
forwarding information base-dependent throughput (6.3) forwarding information base-dependent throughput (6.3)
forwarding information base-dependent latency (6.4) forwarding information base-dependent latency (6.4)
7. Security Considerations 7. Security Considerations
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V5H 4M2 V5H 4M2
Phone: +1 604 454 3516 Phone: +1 604 454 3516
Email: Guy_Trotter@agilent.com Email: Guy_Trotter@agilent.com
Full Copyright Statement Full Copyright Statement
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Terminology for FIB based Router Performance July, 2001
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and distributed, in whole or in part, without restriction of any and distributed, in whole or in part, without restriction of any
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Terminology for FIB based Router Performance July, 2001
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