Bay Networks Remote Annex Service manual

Part No. 166-024-833 Rev. A
December 1996
to the Remote Annex
Administrator’s Guide
for UNIX
Multilink PPP
Addendum

Copyright ©1996 Bay Networks, Inc.
All rights reserved. Printed in the USA. December 1996.
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iii166-024-833 Rev. A
Contents
Multilink PPP Addendum to the Remote Annex Administrator’s Guide for UNIX
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Supported MP Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Unsupported MP Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
MP Functional Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
The MP Process. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Bundling Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Closing Member Links. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Security Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
MP Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
MP Operational Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
MP Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
mp_endpoint Class and Address Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
The acp_userinfo File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Administration of MultiLink PPP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
SNMP Proprietary MIB Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
MP Selectable Parameters for the Remote Annex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

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Contents
iv

1166-024-833 Rev. A
Multilink PPP Addendum to the Remote Annex
Administrator’s Guide for UNIX
This addendum is designed as a supplementary document to be
used in conjunction with the Remote Annex Administrator’s Guide for
UNIX, the Remote Annex 6300 Supplement to the Remote Annex
Administrator’s Guide for UNIX, and the Annex Manager User Guide.
This addendum covers the following topics:
❑Overview
❑Supported and Unsupported MP Features
❑MP Function and Process Information
❑MP Configuration
❑The acp_userinfo File
❑Administration of Multilink PPP
❑SNMP Proprietary MIB Objects
❑MP Parameters for Annex
❑PPP Parameters
Overview
Multilink PPP (MP) is a protocol standard that provides a method to
adjust the bandwidth of a connection between two network devices
to accommodate dynamically changing network loads. This
implementation of MP is based on the RFC1990 technical
specification.
Member Links and
Bundle Links To support this protocol, the RA 6300 PPP protocol stack has been
extended to allow one or more PPP links to form a single virtual PPP
interface for the network layer protocols, such as IP, IPX and
AppleTalk over PPP. In this document, the virtual PPP interface is
referred to as the bundle and the PPP links are referred to as member
links.

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2
When a member link is established, several options are negotiated
between the two endpoints of the connection to allow each to assign
the new link to a bundle. Refer to Figure 1 for a representation of the
functional flow.
Supported MP Features
The following MP features are supported for this software release:
❑Short and Long Sequence Header
❑Fragmentation
❑Local Endpoint Discriminators:
❑NULL
❑IP
❑MAC (alias is DEFAULT)
❑PSNDN
❑All Remote Endpoint Discriminators
❑Maximum Reconstructed Receive Unit
Unsupported MP Features
ThefollowingMPfeaturesarenotsupported forthis softwarerelease:
❑Local Endpoint Discriminators:
❑Locally Assigned Address
❑Magic Number Blocks

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Multilink PPP Addendum to the Remote Annex Administrator’s Guide for UNIX
166-024-833 Rev. A
MP Functional Diagram
Figure 1. MP Functional Flow
Data Link Layer
LOW
PPP
Member
syn20*
PPP
Member
syn21* Authentication PAP/CHAP
Local LCP
IP/ IPX/ ATNetwork Layer
PPP ACP User
ProfileNCPData Link Layer
HIGH
Multilink PPP
PPP PPP
Physical Layer
Bundle
mp1
Remote Member Member
Link1 Link2

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The number of member links can be adjusted to increase bandwidth
in response to network traffic over the bundle. Active bandwidth
control protocols, such as BACP/BAP, are not supported in this
release. However, the RA 6300, using the security services of RACP,
can restrict the maximum number of member links permitted to join
a bundle, if this control is required by the network administrator. For
more information, see mp_max_links on page 11.
The MP Process
The following table outlines the processing of a typical MP
connection:
When... Then... For More Information
See...
a remote user opens
PPP link1, link control protocol (LCP) establishes and
negotiates the data
link options for PPP
link1.
Remote Annex
Administrator’s Guide
for UNIX
the LCP negotiation is
successful, PPP link1 requests (optional)
authentication by
CHAPor PAPsecurity
protocols.
Remote Annex
Administrator’s Guide
for UNIX
the PPP link1 is
authenticated
(optional) by CHAP or
PAP security protocols,
the member link
attempts to join a
bundle.
Remote Annex
Administrator’s Guide
for UNIX

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166-024-833 Rev. A
When... Then... For More Information
See...
the member link’s MP
LCP options and
authentication
information match an
existing bundle,
the bundle checks that
themaximum number
of member links will
not be exceeded and
adds the member link
to the bundle.
RFC1990/
mp_max_links
the member link’s MP
LCP options and
authentication
information do not
match an existing
bundle,
the bundle checks that
themaximum number
of member links has
not been reached and
establishes a new
bundle.
RFC1990/
mp_max_links
a bundle determines
that a network layer
protocol needs to be
transported,
the network control
protocol (IPCP, IPXCP,
ATCP) establishes and
negotiates the
network protocol
options and attaches
the bundle to a proper
network route.
Remote Annex
Administrator’s Guide
for UNIX

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Bundling Scenarios
The following four scenarios are used as guidelines for bundling
member links.
Closing Member Links
Terminate-Request
Terminate-Ack Member links may be terminated according to normal PPP LCP
procedures using LCP Terminate-Request and Terminate-Ack
packetson the memberlink.Receiptof aTerminate-Ackisa sufficient
indicator that any MP packets ahead of it are at no special risk of loss.
If there is... Then...
no authentication and no
discriminator, all new links must be joined to one bundle.
a discriminator but no
authentication, if the discriminator matches, the new member link must join a matching
bundle.
if the discriminator does not match, a
new bundle must be established.
no discriminator but
authentication is successful, the authenticated match must join a matching bundle.
the authenticated mismatch must
establish a new bundle.
a discriminator and
authentication is successful, if the discriminator and authentication match, the new member link must join a
matching bundle.
if the discriminator and/or
authentication is mismatched, a new
bundle must be established.

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Security Considerations
It is important to understand that LCP and authentication
negotiations do not occur on the bundle itself. These phases occur on
the member links. Refer to Figure 1.
MP Configuration
All PPP port parameters still apply to MP bundled links. See the
Remote Annex Administrator’s Guide for UNIX for more information.
The MP configuration information is as follows:
(continued on next page)
Option Description MP Parameter
ppp_ncp This option makes MP
active. In order for NCP
to recognize MP as a
valid protocol, you must
set ppp_ncp to all or to
include mp. If you do not
set this option, NCP will
ignore all MP bundling
implementation.
mp
Short Sequence
Number Header
Format (SSNHF),
LCP option 18
This option advises the
peer that the
implementation expects
to receive fragments
with short, 12-bit
sequence numbers. By
default, sequence
numbers are 24-bits long.
The RA 6300 will
always request this
option.

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Option Description MP Parameter
Multilink
Maximum
Reconstructed
Receive Unit
(MRRU),
LCP option 17
This option initiates MP.
The RA 6300 will
support an MRRU of
1500 octets or less for the
local value (will accept
any reasonable value for
the remote MRRU). This
option also advises the
peer that the
implementation will be
able to reconstruct a PPP
packet whose
information will contain
the number of bytes as
Max-Receive-
Reconstructed-Units
(MRRU).
mp_mrru
Endpoint
Discriminator,
LCP option 19
This option presents
identification of the
system transmitting the
packet. It advises a
system that the peer on
this link could be the
same as the peer on
another existing link. If
this option distinguishes
a peer from all others, a
new bundle is created.
The RA 6300 will accept
all remote class requests,
butonly supportsNULL,
MAC, IP, and PSNDN
locally.
mp_endpoint_class,
mp_endpoint_address

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MP Operational Characteristics
MP Load Balancing The bundle distributes fragmented packets over all active member
links.
MP Fragmentation
Bypass Packetssmallerthanafixedsizearenotfragmentedinordertoreduce
processing load caused by reassembly at the remote endpoint.
MP Parameters
ppp_ncp Allows you to set the mode for NCP negotiations for MP. You must
set this parameter to all or include mp in order to negotiate MP over
NCP.
mp_mrru Sets the upper limit of the MRRU LCP negotiation. All LCP
negotiations will start with this value. Downward negotiation is
allowed.
❑Default = 1500
❑Minimum value = 64
❑Maximum value = 1500

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mp_endpoint_
class Sets the value of the local Endpoint Discriminator Class to one of the
following allowed classes. (The remote endpoint is allowed to use all
classes specified in RFC 1990.)
❑Default = MAC (class 3)
❑Accepted values:
NULL, IP, MAC, PSNDN, DEFAULT (alias for MAC)
mp_endpoint_
address Sets the value of the Endpoint Discriminator Address for Endpoint
Discriminator Classes that allow user-configured information. This
parameter is only accessed when set to PSNDN (Public Switched
Network Directory Number).
❑Default = not set or empty string
❑Minimum length = 0 characters
❑Maximum length = 15 characters
mp_endpoint Class and Address Example
PSNDN - Public
Switched Network
Directory Number
A telephone number, up to 15 numeric characters long.
Example: 16172728140
Selecting... Causes the RA 6300...
NULL to use the NULL Endpoint Discriminator.
IP to use the ethernet interface IP address of the RA 6300
for the Endpoint Discriminator Address.
MAC to use the MAC address of the ethernet interface of the
RA 6300 for the Endpoint Discriminator Address.
PSNDN to use the value stored in the mp_endpoint_address
parameter for the Endpoint Discriminator Address.
DEFAULT to use the default Endpoint Discriminator Class (MAC).

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The acp_userinfo File
The identity of the bundle is not fully qualified until the LCP
Endpoint-Discriminatorandthe(optional)authenticationprocessing
has been done. After this process is complete, the bundle policy can
be determined and enforced.
mp_max_links Controlsthetotalnumber ofsimultaneouslyactivePPP links thatcan
be joined in the identified bundle. If this number is exceeded, by
allowing the link to become fully established, the RA 6300 will abort
the PPP link attempting to join the bundle.
❑Default value = 1
❑Minimum value = 1
❑Maximum value = 255 (RA 6300 only supports 30 channels)
mp_max_links Example user username=myname;group=developers
climask telnet end
mp_max_links 3
end
Administration of MultiLink PPP
Several extensions are added to allow management of MP from the
network and from the administrative utilities (host-based na and RA
6300-based admin). Additional status information is also available
through the CLI netstat command and SNMP proprietary MIB
objects.

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netstat -i This command lists bundles as devices named “mp<n>” where <n>
is a number assigned when the bundle is created. Member links
appear but do not have associated addresses, since they are
represented by the bundle as a single interface to the network layer.
A bundle has an address after it completes the NCP negotiations
selected for that connection.
When B-channel assigned addresses are used by MP, only the
address of the first channel called is used. All future calls use
the same IP, IPX, and IPX-net as the first call.
netstat -i Example The following example displays a bundle with two links:
annex# net -i
You may notice that there is an * after the two member links, syn20*
andsyn21*.Youcanusethisasavisualcueofthe netstat-icommand.
Itisanindicatorthattheinterfaceisnotcompletelyconfiguredorthat
itmight be a member link. Use the netstat -ip commandonamember
link, syn20* or syn21*, to identify the bundle to which it belongs.
Formoreinformationonthe interfacestatusinformation, refer
to your Remote Annex Administrator’s Guide for UNIX.
Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Collis
en0 1500 132.245.66 132.245.66 85422 0 30832 1 0
en0 1500 32004-32005 32005.243 85422 0 30832 1 0
pri0* 1500 none none 0 0 0 0 0
lo0 1536 127 127 0 0 0 0 0
syn20* 1500 none none 73 0 105 0 0
mp1 1524 132.245.252 132.245.252 129 0 123 0 0
syn21* 1500 none none 65 0 100 0 0
en0 576 80230066 00802d02cea1

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netstat -ip This command has been extended to provide MP information,
including negotiated MP LCP options. If the command is issued for
amemberlink, the MP statusblockidentifiesthe bundle device name
to which the link has been attached.
netstat -ip Bundle
Example annex# net -ip mp1
*** LCP Status ***
State Current: Open Prior: Open
Options Local: Remote:
MRU 1500 1524
MRRU 1500 1524
Short Sequence Off Off
Endpoint Disc 3:00-80-2d-02-ce-a1 3:00-c0-7b-41-6e-2b
*** NCP (IPCP) Status ***
State Current: Open Prior: Ack received
Options Local: Remote:
IP addresses 132.245.66.37 [ANX] 132.245.252.22 [REM]
Compression VJ TCP/IP 15/1 VJ TCP/IP 15/1
*** NCP (CCP) Status ***
State Current: Request sent Prior: Request sent
*** NCP (MP) Status ***
State Current: Open Prior: Closed
NCP states not negotiated are not displayed.

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netstat -ip Member Link
Example annex# net -ip syn1
*** LCP Status ***
State Current: Open Prior: Open
Options Local: Remote:
MRU 1500 1524
Auth type None None
LQM None None
Magic 0x8d4ba408 None
MRRU 1500 1524
Short Sequence Off Off
Endpoint Disc 3:00-80-2d-02-ce-a1 3:00-c0-7b-41-6e-2b
*** NCP (CCP) Status ***
State Current: Open Prior: Closed
Attached to bundle mp1
ThefollowinglistdetailsthenewMPOptionsavailableinthisrelease.
For more information on the remaining standard options, see the
Remote Annex Network Administrator’s Guide for UNIX.
netstat -b Anewoption,-b,displaysMPbundleinformationforcurrentlyactive
bundles.
The syntax for netstat -b is:
netstat -b [bundle]
If the bundle ID is not specified, then all active bundle information is
displayed. If the bundle ID is specified (e.g. netstat -b mp1) then the
specified bundle information is displayed.

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netstat -b Example Thefollowingexampledisplaysabundlewithtwolinks.Themember
link PPP statistics details are repeated for each link in the bundle:
annex# netstat -b
[Bundle: mp1]
MP packets sent: 133 MP packets accepted: 154
Packets fragmented: 62 Fragments discarded: 1
Fragments generated: 195 Fragments assembled: 154
Peak links used: 0 Current links used: 2
Frames sent: 133 Frames received: 308
Frames discarded: 2
Dropped: 0 No memory: 0
Missing mbuf: 0 Net down:0
Short: 0 Unknown codes: 0
[Bundle: mp1][Member link: syn12]
Frames sent: 300 Frames received: 333
Frames discarded: 0
Dropped: 0 No memory: 0
Missing mbuf: 0 Net down:0
Short: 0 Unknown codes: 0
[Bundle: mp1][Member link: syn13]
Frames sent: 300 Frames received: 315
Frames discarded: 0
Dropped: 0 No memory: 0
Missing mbuf: 0 Net down:0
Short: 0 Unknown codes: 0

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MP Statistics The following table describes the MP data displayed when entering
anetstat-b command:
MP Statistics Description
MP packets sent: Packets sent to all NCPs.
MP packets accepted: Packets received from all NCPs.
Packets fragmented: Packets that were fragmented.
Fragments discarded: Fragments lost.
Fragments generated: Fragments that were generated.
Fragments assembled: Fragments successfully assembled.
Peak Links used: Peak links used during the lifetime of the
bundle.
Current Links used: Current links in use.