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Cisco 10000 Series Router Software Configuration Guide
OL-2226-23
Chapter 22 Configuring Multilink Point-to-Point Protocol Connections
MLP on LNS
PPP multilink links max Command
Support for the
ppp multilink links max
command is new in the Cisco IOS 12.2(33)SB release, to
distinguish between single and multimember MLP on LNS bundles. The default maximum number of
links for the Cisco 10000 series routers is 10. The
ppp multilink links max 1
command is required for
single-member bundles.
Performance and Scalability of MLP on LNS
The following commands allow for better scaling when used in configuring MLP on LNS:
•
Configure the
hold-queue
command
in interface configuration mode for the trunk interfaces in
which the L2TP tunnel is negotiated. For example:
Router(config-if)#
hold-queue 4096 in
•
Configure the following commands and recommended values on the virtual template interface:
Router(config-if)#
ppp max-configure
110
Router(config-if)#
ppp max-failure
100
Router(config-if)#
ppp timeout retry
5
Router(config-if)#
keepalive
30
•
Configure the
lcp renegotiation always
command on the VPDN group to renegotiate between L2TP
access concentrator (LAC) and LNS. The maximum number of multilink member links that can be
configured on the Cisco 10000 series routers is up to 20440. Different combinations of bundle
configurations can be configured on the box at any given time based on resource availability.
For more information, see the
Scalability and Performance
chapter in this guide.
PXF Memory and Performance Impact for MLP on LNS
PXF performance is measured as follows:
•
Packet buffer usage
The number of packet buffers available on the PRE3 is 832K small buffers (for packet sizes of 768
bytes or less) and 120K large buffers (for packet sizes greater than 768 bytes). With full scaling of
12280 bundles (2040 multilink and 10240 single link), the average number of buffers is 69.4 small
buffers and 10.0 large buffers per bundle for a total of 79.4 buffers per bundle.
Member link
single-member bundle
1
1
1
0
Member link
multi-member bundle
1
1
1
1
1.
A virtual circuit connection identifier (VCCI) is a variable that identifies a virtual circuit connection between two nodes.
2.
A hardware interface descriptor block (HWIDB) represents a physical interface, which includes physical ports and
channelized interface definitions.
3.
A software interface descriptor block (SWIDB) represents a logical sub interface such as permanent virtual circuit (PVC) or
virtual LAN (VLAN), or a Layer 2 encapsulation (Point-to-Point Protocol (PPP)), or high-level data link control (HDLC).
4.
An HQF resource that is used by the RP and PXF to program physical layer scheduling for an interface. It could be considered
an instance of physical layer scheduling; Cisco 10000 series routers currently support 16K such instances. All bundle
interfaces (single or multi-member bundles) use one instance of this resource. For single-member bundles the scheduling is
done at the logical layer. All members of multi-member bundles are scheduled at the physical layer, so each member link in
a multi-member bundle uses one instance.
