Cisco Systems 1000 Series Manual De Usuario

Using the Virtual Private Dialup Network (VPDN) Group Session Limiting feature, you can limit the 
number of VPDN sessions allowed per VPDN group. VPDN session limits can increase performance and 
reduce latency for routers that are otherwise forced to operate at high capacity.

For more information about VPDN Group Session Limiting, see the feature documentation at:

The PPPoE Session Limit Support feature prevents the router from using too much memory for virtual 
access by limiting the number of PPPoE sessions that can be created on a router or on all Ethernet 
interfaces and subinterfaces as well as ATM interfaces and subinterfaces.

For more information about PPPoE session limiting, see the feature documentation at:

To prevent the virtual access subinterfaces from being registered with the Simple Network Management 
Protocol (SNMP) functionality of the router and using up the memory, do not use the SNMP 
management tools of the router to monitor PPP sessions. Use SNMP views to isolate the bulk queries 
and accidental requests. 

Use the no virtual-template snmp command to disable the SNMP management tools:

Router(config)# no virtual-template snmp

The default value of Gigabit Ethernet and 10 Gigabit Ethernet interfaces is 375 packets for the input and 
output hold queues. If the interfaces are required to handle a high rate of control packets, such as LCP, 
IPCP, PPP, L2TP, and DHCP, the default value may not be sufficient. To ensure high scalability, set the 
access interface input and output hold queue to 4096:

Router(config)# interface gig1/0/0

Router(config-if)# hold-queue 4096 in

For PPP sessions, the keepalive command sets the keepalive timer for a specific interface. To ensure 
proper scaling and to minimize CPU utilization, set the timer for 60 seconds or longer. The default value 
is 10 seconds:

interface Virtual-Template1

 ip unnumbered Loopback1

 keepalive 60

 no peer default ip address

 ppp authentication pap