Avaya MPOA and NHRP, MPOA User Manual
BayRS Version 14.00
Part No. 309249-14.00 Rev 00
September 1999
4401 Great America Parkway
Santa Clara, CA 95054
Configuring MPOA and NHRP Services
Copyright © 1999 Nortel Networks
All rights reserved. Printed in the USA. September 1999.
The information in this document is subject to change without notice. The statements, configurations, technical data,
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309249-14.00 Rev 00
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Contents
Preface
Before You Begin .............................................................................................................xiii
Text Conventions .............................................................................................................xiv
Acronyms ........................... .......................... .......................... ......................... .................xvi
Hard-Copy Technical Manuals . .............................................. ...... ...... ............................xviii
How to Get Help ............................................................................................................xviii
Chapter 1
Understanding MPOA and NHRP
ATM General Information ................................................................................................1-1
Multi-Protocol over ATM ..................................................................................................1-2
MPOA Logical Components .....................................................................................1-3
MPOA Basic Elements .............................................................................................1-4
Establishing a Network Cut-Through .... ...... ....... ...... ....... ...... ...... ....... ...... ....... ...... ...1-5
NHRP .............................................................................................................................1-7
For More Information ......................................................................................................1-8
Where to Go Next ...........................................................................................................1-9
Chapter 2
Starting MPOA and NHRP Services
Starting Configuration Tools ...........................................................................................2-1
Starting the MPOA Server ..............................................................................................2-2
Creating an MPOA Service Record .........................................................................2-2
Adding an MPOA Server ..........................................................................................2-4
Starting NHRP on an ATM LEC, PVC, or Classical IP Service ......................................2-5
Starting NHRP on an ATM LEC Service ..................................................................2-6
Starting NHRP on an ATM PVC Service ................................................................2-11
Starting NHRP on an ATM Classical IP (RFC 1577 SVC) Service ........................2-14
Where to Go Next .........................................................................................................2-16
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v
Chapter 3
Customizing MPOA Services
Disabling and Reenabling an MPOA Service .................................................................3-2
Setting the MPS Address Generating Mode ...................................................................3-3
Specifying an MPS Control ATM Address ......................................................................3-5
Network Prefix ..........................................................................................................3-5
User Suffix ................................................................................................................3-6
Disabling and Reenabling MPOA Servers ......................................................................3- 8
Specifying the MPS Configuration Mode ......................................................................3-10
Specifying a LECS ATM Address .................................................................................3-11
Network Prefix ........................................................................................................3-12
User Suffix ..............................................................................................................3-12
Configuring a Unique Selector Byte for an MPS Address ............................................3-14
Defining MPS Timer Values ..........................................................................................3-16
Setting the Transmission Interval for MPOA Keepalive Packets .............................3-17
Setting the Valid Lifetime for Keepalive Packets .....................................................3-18
Setting the Initial Retry Time ..................................................................................3-19
Setting the Maximum Retry Time ...........................................................................3-21
Setting the Time to Wait for Responses to Resolution Requests ...........................3-22
Setting the Valid Interval for Replies to Resolution Requests ................................3-23
Defining MPS Cache Values ........................................................................................3-25
Setting the Initial Cache Size .................................................................................3-25
Setting the Maximum Cache Size ..........................................................................3-26
Deleting MPOA Servers ...............................................................................................3-28
Deleting an MPOA Service Record ..............................................................................3-29
Where to Go Next .........................................................................................................3-31
Chapter 4
Customizing NHRP Services
Accessing NHRP Client and Server Global Parameters ................................................4-2
Disabling NHRP on an LEC or PVC or Classical IP Service ..........................................4-4
Deleting NHRP from an LEC or PVC or SVC Service ....................................................4-6
Deleting NHRP Globally .................................................................................................4-7
Where to Go Next ...........................................................................................................4-8
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Appendix A
Site Manager Parameters
Accessing ATM Parameters ........................................................................................... A-1
Accessing ATM MPOA Pa rameters Through a Window Path ................................. A-2
Accessing ATM MPOA and NHRP Parameters Through a Menu Path ................... A-2
MPOA Service Parameters ............................................................................................ A-3
MPOA Server (MPS) Parameters .................................................................................. A-5
MPS Add Parameters .............................................................................................. A-5
MPS Operational Parameters ................................................................................. A-7
NHRP Global Parameters ............................................................................................ A-14
NHRP Interface Parameters ........................................................................................ A-19
Appendix B
BCC Parameters
MPOA Service Record Parameters ............................................................................... B-2
MPS Parameters ........................................................................................................... B-4
MPOA Server Parameters ............................................................................................. B-8
NHRP Global Parameters .............................................................................................. B-9
NHRP Interface Parameter .......................................................................................... B-13
Appendix C
Monitoring MPOA and NHRP Services
Online Help for show Commands .................................................................................. C-2
show mpoa caches ........................................................................................................ C-3
show mpoa caches all .............................................................................................C-3
show mpoa caches egress ......................................................................................C-4
show mpoa caches ingress .....................................................................................C-6
show mpoa server .........................................................................................................C-7
show mpoa server configuration ............................................................................. C-7
show mpoa server stats .......................................................................................... C-9
show nhrp ....................................................................................................................C-12
show nhrp client configuration ............................................................................... C-12
show nhrp client stats ...........................................................................................C-13
show nhrp interfaces ............................................................................................. C-14
show nhrp server configuration ............................................................................. C-15
show nhrp server stats .......................................................................................... C-15
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vii
Appendix D
Example Configuration
Configuration Diagram ................................................................................................... D-2
BCC Configuration Sequence .......................................................................................D-4
Appendix E
BCC Configuration Tree
for MPOA and NHRP
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Figures
Figure 1-1. ATM Zero-Hop (Cut-Through) Routing .....................................................1-2
Figure 1-2. MPOA with Cut-Through VC ....................................................................1-6
Figure 2-1. Mapping an MPS to an LEC Service .......................................................2-9
Figure D-1. Example MPOA/NHRP Configuration ..................................................... D-2
Figure E-1. BCC Configuration Tree for MPOA and NHRP ....................................... E-2
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ix
Tables
Table D-1. Example Configuration Summary ...........................................................D-3
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xi
This guide describes Nortel Networks implementation of Multi-Protocol over
ATM (MPOA) and Next Hop Resoluti on Protocol (NHRP) servic es, and what you
do to start and customize these services on a Nortel Networks
You can use the Bay Command Console (BCC
MPOA and NHRP on a router. In this guide, you will fi nd instructions for using
both the BCC and Site Manager. Use Site Manager to support any feature not
support by the BCC.
Before You Begi n
Before using this guide, you must complete the following procedures. For a new
router:
Preface
™
router.
™
) or Site Manager to configure
• Install the router (see the installation guide that came with your router).
• Connect the router to the network and create a pilot configuration file (see
Make sure that you are runni ng the lates t versio n of Nortel Netw orks BayRS
Site Manager software. For information about upgrading BayRS and Site
Manager, see the upgrading guide for your version of BayRS.
309249-14.00 Rev 00
Quick-Starti ng Router s , Conf igur ing BaySt ac k Remote Acc ess , or Connecting
ASN Routers to a Network).
™
and
xiii
Configuring MPOA and NHRP Services
Text Con ventions
This guide uses the following text conventions:
angle brackets (< >) Indicate that you choose the text to enter based on the
description inside the brackets. Do not type the
brackets when entering the command.
Example: If the command syntax is:
ping
<
ip_address
ping 192.32.10.12
>, you enter:
bold text
Indicates command names and options and text that
you need to enter.
Example: Enter
show ip {alerts | routes
Example: Use the
dinfo
command.
}.
braces ({}) Indicate required elements in syntax descriptions
where there is more than one option. You must choose
only one of the options. Do not type the braces when
entering the command.
Example: If the command syntax is:
show ip {alerts | routes
show ip alerts or show ip routes
}
, you must enter either:
, but not both.
brackets ([ ]) Indicate optional elements in syntax descriptions. Do
not type the brackets when entering the command.
Example: If the command syntax is:
show ip interfaces [-alerts
show ip interfaces
or
]
, you can enter either:
show ip interfaces -alerts
.
ellipsis points (. . . ) Indicate that you repeat the last element of the
command as needed.
xiv
Example: If the command syntax is:
ethernet/2/1
ethernet/2/1
[<
parameter> <value
and as many parameter-value pairs as
needed.
. . .
>]
, you enter
309249-14.00 Rev 00
Preface
italic text Indicates file and directory names, new terms, book
titles, and variables in command syntax descriptions.
Where a variable is two or mor e words, the words are
connected by an underscore.
Example: If the command syntax is:
show at <
valid_route
valid_route
>
is one variable and you substitute one value
for it.
screen text Indicates system output, for example, prompts and
system messages.
Example:
Set Trap Monitor Filters
separator ( > ) Shows menu paths.
Example: Protocols > I P ide nti fies the I P opt ion on the
Protocols menu.
vertical line (
) Separates choices for command keywords and
|
arguments. Enter only one of the choices. Do not type
the vertical line when enteri ng the command.
Example: If the command syntax is:
show ip {alerts | routes}, you enter either:
show ip alerts or show ip routes, but not both.
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xv
Configuring MPOA and NHRP Services
Acronyms
This guide uses the following acronyms:
AAL ATM adaptation layer
AFI authority and format identifier
ARE ATM Routing Engine
ARP Address Resolution Protocol
ATM asynchronous transfer mode
B-ISDN Broadband Integrated Services Digital Network
CSU channel service unit
DCE data communication equipment
DSU data service unit
DTE data terminal equipment
ELAN emulated local area network
IETF Internet Engineering Task Force
xvi
ILI Intelligent Link Interface
ILMI Interim Local Management I nterface
IP Internet Protocol
LANE local area network emulation
LE LAN emulat ion
LEC LAN emulation client
LECS LAN emulation configuration server
LER label edge router
LES LAN emulat ion server
LLC Logical Link Control
MAC media access control
MIB management inform ation base
MPC MPOA client
MPLS Multiprotocol Label Switching
309249-14.00 Rev 00
MPOA Multi-Protocol over ATM
MPS MPOA server
MTU maximum transmission unit
NHRP Next Hop Resolution Protocol
OC-3 Optical Carrier-level 3
OSPF Open Shortest Path First
PDN Public Data Network
PDU protocol data unit
PHY physical [layer]
PMD physical medium dependent
PT payload type
PVC permanent virtual circuit
RIP Routing Information Protocol
SAAL signaling AAL
SAP service access point
Preface
SAR segmentation and reassembly
SMDS Switched Multimegabit Data Service
SNAP Subnetwork Access Protocol
SNMP Simple Network Management Protocol
SONET/SDH Synchronous Optical Network/Synchronous Digital Hierarchy
SPE synchronous payload envelope
SRM System Resource Module
SSCOP Service Specific Connection Oriented Protocol
SSCS service specific convergence sublayer
SVC switched virtual circuit
UNI user-to-network interface
VC virtual circuit
VCC virtual channel connection
VCI virtual chann el identifier
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xvii
Configuring MPOA and NHRP Services
VCL virtual channel link
VPC virtual path connection
VPI virtual path identifier
WAN wide area network
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You can purchase selected documentation sets, CDs, and technical publications
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• The “Technical Manuals” section lists available printed documentation sets.
How to Get Help
If you purchased a service contract for your Nortel Networks product from a
distributor or authorized reseller, contact the technical support staff for that
distributor or reseller for assistance.
If you purchased a Nort el Net wor ks s ervice pr ogram, c ontact one of the f ollowing
Nortel Networks Technical Solutions Centers:
Technical Solutions Center Telephone Number
Billerica, MA 800-2LANWAN (800-252-6926)
Santa Clara, CA 800-2LANWAN (800-252-6926)
xviii
309249-14.00 Rev 00
Technical Solutions Center Telephone Number
Valbonne, France 33-4-92-96-69-68
Sydney, Australia 61-2-9927-8800
Tokyo, Japan 81-3-5402-7041
Preface
309249-14.00 Rev 00
xix
Chapter 1
Understanding MPOA and NHRP
This chapter descr ibes the c oncepts under lying Multi-pr otocol o ver ATM (MPO A)
and Next-Hop Resolution Protocol (NHRP) and, where appropriate, the specific
ways in which Nortel Networks implements MPOA and NHRP functionality on
its routers. It contains the following information:
Topic Page
ATM General Information 1-1
Multi-Protocol ov er ATM 1-2
NHRP 1-7
For More Information 1-8
Where to Go Next 1-9
ATM General Information
Asynchronous transfer mode (ATM) is a connection-oriented, cell-based
technology that relays traffic across a Broadband Integrated Services Digital
Network (B-ISDN). ATM provides a cost-effective way of transmitting voice,
video, and data across a network. For more information about ATM, see
Configuring ATM Services.
309249-14.00 Rev 00
1-1
Configuring MPOA and NHRP Services
Multi-Protocol over ATM
As defined by the ATM Forum, Multi-Protocol over ATM (MPOA) maps routed
and bridged traffic flows to ATM SVCs, thereby removing many performance
limitations imposed by the mult ihop routing of individual packets. This technique
of mapping identifiable traffic flows to virtual channels creates network
“shortcuts” between source and destination clients, and is generally referred to as
cut-through or zero-hop routing. Fi gur e 1-1
can communicate efficiently over an independent layer 2 (ATM) virtual channel,
established by means of MPOA and NHRP negotiations.
shows ho w users on LAN 1 or LAN 2
MPOA server 1
(MPS)
MPOA
MPOA client 1
(MPC)
ATM ELAN, PVC
or RFC 1577 SVC
NHRP NHRP
ATM ELAN
Cut-through (zero-hop) route (ATM SVC)
Established through MPOA/NHRP negotiations
MPOA servers
(MPSs)
ATM ELAN, PVC
or RFC 1577 SVC
ATM ELAN
MPOA server
(MPS)
MPOA
MPOA client 2
(MPC)
LAN 2LAN 1
BCC0029A
n
Figure 1-1. ATM Zero-Hop (Cut-Through) Routing
MPOA supports communication between an MPOA client (MPC), typically an
ATM edge device or switch, and its MPOA server (MPS), typically a router.
NHRP supports communication between MPSs.
1-2
309249-14.00 Rev 00
Understanding MPOA and NHRP
Although the connection between any two MPSs can be supported by an ATM
PVC, RFC 1577 SVC (ATM Classical IP), or emulated LAN (ATM LANE), the
connection between any MPC and its MPS must always be supported by an
ELAN, as shown in Figure 1-1 on page 1-2
.
Cut-through routing i s based o n the f act t hat, in most cases , data t ransfe r occur s at
a steady rate of flow. For example, data or file transfer from one legacy Ethernet
LAN to a remote counterpart usually involves multiple frames. A file transfer of
approximately 45 KB requires about 30 Ether net frames, all address ed to the same
destination.
In an MPOA environment, it is possible to:
• Identify, from the address field in the first frame of a data/file transfer, the
recipient of that data or file.
• Establish an SVC to the recipient.
The software then disassembles all 30 or so frames into approximately 900 ATM
cells and transmitts them to the reci pient by way of th e virtual channel provided
by the SVC.
Network performa nce i mp roves as the cells follow a predetermined di re ct path, in
contrast to the hop-by-hop routing of the Ethernet frames. Network performance
improves markedly in the case of steady-stream deterministic data flows, such as
video.
MPOA Logical Components
MPOA operati ons are based on l ogical compone nts, which can be im plemented in
various configurations of hardware and software. MPOA logical components
include the following:
•MPOA clients
An MPOA client (MPC) resides in each ATM edge device (for example, an
ATM switch) served by an MPOA router. BayRS does not provide MPC
functionality. The primary function of the MPC is t o act, in ATM termi nology,
as an ingress or egress point for traffic establishing and subsequently using
network cut-throughs.
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Configuring MPOA and NHRP Services
The MPC moni tors traffic flows between a local source and remote
destinations. Wh en traffic volume between a sour ce and a d estin ation exceeds
a preconfigured threshold level (for example x packets to the same network
layer address in y seconds), the MPC attempts to set up an SVC between the
source and destination workstations.
In attempting to set up an SVC, the MPC first looks in a local cache of
network layer-to-ATM address mappings. If the MPC finds the destination
address in its local cac he, it immediately be gins to est ablish the SVC. If it f ails
to locate the destination address in the local cache, it generates an MPOA
address resolution request to an adjacent MPOA server.
• MPOA routers
Each MPOA router that serves MPCs, directly or indirectly, includes a
collection of logical functions that map network layer addresses to ATM
addresses. Each MPO A router maintai ns tables of adjacent network layer (IP),
MAC laye r, and ATM addresses, in addition to s tandar d ro uting tabl es der ived
from a routing protocol (generally OSPF or RIP).
MPOA routers communicate over NHRP to map network layer addresses to
ATM addresses. BayRS provides MPOA router functionality to map IP
addresses to their ATM c ounterparts.
• MPOA servers
The MPOA server (MPS) is a logical function that mediates between local
MPCs and the MPOA router. It receives MPOA address resolution requests
from MPCs and passes them to the MPOA routing function. The MPOA
router, using NHRP, resolves the address and passes the requested ATM
address back to the MPS. The MPS, in turn, forwards the resolved address to
the requesting MPC. BayRS provides MPOA server functionality.
MPOA Basic Elements
MPOA services provid ed by each Nort el Networks router depend on the e xistence
of:
• An ATM emulated LAN (using LANE) between each MPC and its MPS.
• An ATM emulated LAN, ATM Classical IP (RFC 1577 SVC), or an ATM
PVC between any two MPSs. (See Figure 1-1 on page 1-2
• NHRP to resolve ATM and IP source and destination addresses.
• IP to route NHRP packets and other traffic between MPSs.
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.)
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Understanding MPOA and NHRP
For more information about Go to
IP
LANE
NHRP “NHRP” on page 1-7
Establishing a Network Cut-Through
MPOA componen ts and elements fu nction together to establish an SVC bet ween a
source host and a destination host, as follows:
1.
A local MPC monitors traf f ic f lo w and mainta ins a count of pack ets addre ssed
over a specific interval to remote hosts. When the count exceeds a threshold
value, the MPC attempts to establish an SVC to the host.
To establish the virtual connection, the MPC needs the ATM address of the
host.
2.
The MPC first checks a local address resolution cache to map the known
network layer address with an ATM equivalent.
3.
If the cache search fails, the MPC issues an MPOA resolution request to the
local MPS function resident on the adjacent router.
4.
The local MPS hands the resolution request to the MPOA router component.
5.
The MPOA rou ter gener ates an NHRP address resolut ion reque st for t he ATM
address of the destination host. Standard routing protocols move the NHRP
request through the network toward the des tination host. Eventually, the
NHRP request reaches the egress router, that is, the router that serves the
target host.
Configuring IP Services
Configuring ATM Services
6.
7.
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The egress router forwards the request to its MPS entity.
The remote MPS provides the ATM address of the destination host to its
NHRP entity.
If the destination host is connected to a legacy LAN, the MPS provides the
ATM address of the router that conn ect s to the legacy LAN. If the destination
host is ATM-attached, the MPS provides the ATM address of the destination
host.
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Configuring MPOA and NHRP Services
8.
The remote MPOA router generates an NHRP address resolution reply
containing the ATM address pr ovi ded b y the MPS. Stan dard ro uting prot ocols
move the NHRP reply through the network to the local MPOA router.
9.
The local MPOA rout er sends the resolved addr ess to the MPS, which then
caches and sends t he r esolved addre ss to the MPC that init iat ed the resolutio n
process.
10.
The local MPC caches the address resolution information and establishes an
SVC to the remote MPC, establish ing the netw or k cut-thr ough connection f or
more efficient communication.
ATM MPC
10BASE-T
ATM network
ATM MPS
ELAN 1
ELAN 2
ATM MPC
10BASE-T
Figure 1-2. MPO A with Cut-Through VC
Note again t hat in Figure 1-2, the logical connection between any two MPSs can
be an ATM PVC or RFC 1577 SVC (ATM Classical IP) instead of an ELAN,
depending on your network topology requirements.
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ELAN 3
ELAN 4
ATM MPS
Key
Cut-through VC
Logical connection
NHRP control VC
ATM0055A
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NHRP
Understanding MPOA and NHRP
NHRP is an address resolution protocol described in Internet RFC 2332.
As defined by the RFC, NHRP provides address resolution services by mapping
“internetworking layer addresses to NBMA subnetwork addresses.” As
implemented by N ortel Networks, N HRP resolves IP to ATM addresses.
The IETF draft specifies behavior for NHRP clients and NHRP servers.
• The NHRP client (NHC) generates NHRP address resolution requests on
behalf of applications such as a local MPS.
• The NHRP server (NHS) responds to NHRP address resolution requests by
generating NHRP address resolution replies. For this purpose, the NHS
maintains a next-hop cache.
NHRP supports address resolution using seven formatted message types.
• NHRP resolution request
An NHRP resolution request is generated by an NHC and routed through the
ATM topology. Functionally eq uivalent to a stan dard ARP requ est, it contai ns
the layer 3 and layer 2 address of the originator, the layer 3 address of the
target destination, and a blank field reserved for the layer 2 address of the
target. As implemented by Nortel Networks, the NHRP resolution request
contains the IP and ATM addresses of the originator and the IP address of the
target.
• NHRP resolution reply
• NHRP registration request
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An NHRP resolution reply is generated by an NHS in response to an NHRP
resolution request. Like an NHRP resolution request, it is routed through the
ATM topology. It is functionally e qui v alen t to a stan dard ARP response in th at
it replicates the information in the NHRP resolution request and supplies the
requested layer 2 (ATM) address.
An NHRP registration request is generated by an NHC and directed toward
the local NHS. The NHRP registration request is used to register address
mapping data gathered by the NHC with the NHS. The NHS places mapping
data in its next-hop cache.
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Configuring MPOA and NHRP Services
• NHRP registration reply
An NHRP registration reply is generated by an NHS in response to an NHRP
registration request. It provides positive or negative acknowledgment of data
receipt.
• NHRP purge request
An NHRP purge request can be generated by either an NHC or an NHS. It
requests the recipi ent to delete pr evio usly cached informatio n that has become
invalid.
• NHRP purge reply
An NHRP purge reply is generated by either an NHC or an NHS in response
to an NHRP purge request. It provides positive acknowledgment of data
receipt.
• NHRP error indication
An NHRP error indication can be generated by either an NHC or an NHS. It
conveys error status to the sender of an NHRP message.
For More Information
1-8
For more information about MPOA and NHRP, refer to the following documents:
Heinanen, J. Multiprotocol Encapsulation over ATM Adaptation Layer 5.
RFC 1483. Network Working Group. July 1993.
Cole, B., N. Doraswamy, D. Katz, J. Luciani, D. Piscitello. NBMA Next Hop
Resolution Protocol (NHRP). RFC 2332. April 1998.
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Where to Go Next
Use the following table to determine where to go next.
If you want to Go to
Understanding MPOA and NHRP
Learn about ATM and PVCs.
Learn about LAN emulation.
Start MPOA and NHRP services. Chapter 2
Change defa ult settings for MPOA server parameters. Chapter 3
Change default settings for NHRP client or server
parameters.
Obtain information about Site Manager parameters. Appendix A
Obtain information about BCC parameters. Appendix B
Monitor ATM using the BCC show commands. Appendix C
Review an example MPOA/NHRP configuration
sequence.
Review the BCC configuration tree for MPOA and NHRP
services.
Configuring ATM Services
Chapter 4
Appendix D
Appendix E
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