Cisco 10000-2P2-2DC Software Guide - Page 499

Chapter 22 Configuring Multilink Point-to-Point Protocol Connections MLP on LNS Member link 1 1 1 0 single-member bundle Member link 1 1 1 1 multi-member bundle 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. 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. OL-2226-23 Cisco 10000 Series Router Software Configuration Guide 22-21