Juniper JUNOSE 11.1.X - LINK LAYER CONFIGURATION 4-7-2010, Configuration Manual

Page: 53 / 774

Rate Limiting for F5 OAM Cells
The router implements rate limiting for ATM F5 OAM cells to protect the
corresponding ATM interface from denial-of-service (DoS) attacks. The interface
discards control packets when the rate of control packets received exceeds the rate
limit for ATM interfaces.
An ATM interface has a rate limit control that is non-configurable and always in effect;
the rate limit is the same for all ATM interfaces. In addition, each ATM VC maintains
its own state and statistics counters for tracking the rate. The rate limit for ATM OAM
cells is approximately 5 packets per second.
For an ATM VC, the router increments the InOamCellDiscards statistics counter in
the
show atm vc atm command display to track the number of OAM cells received
on this circuit that were discarded. The InOamCellDiscards counter operates on a
per-circuit basis, not on a per-interface basis.
For examples of the show atm vc atm command display, see “show atm vc atm”
on page 94.
Before You Configure ATM
Before you configure an ATM interface, verify that you have installed the physical
module (such as an OC3 module) correctly. For more information about
preconfiguration procedures, see the
ERX Hardware Guide or the E120 and E320
Hardware Guide .
Also have the following information available:
■
Interface specifiers for the ATM interfaces that you want to create
For more information about specifying ATM interfaces and subinterfaces on E
Series routers, see Interface Types and Specifiers in
JUNOSe Command Reference
Guide .
■
Virtual path and channel numbers for each virtual circuit you want to create
■
IP addresses and subnet mask assignments for IP interfaces
You can configure the following types of dynamic interfaces over ATM:
■
IP over static ATM 1483 (IPoA)
■
IP over PPP over static ATM 1483
■
IP over PPPoE over static ATM 1483
■
IP over bridged Ethernet over static ATM 1483
■
IP over MLPPP over static ATM 1483
■
ATM 1483 over static ATM AAL5 over ATM
For information about creating these dynamic configurations, see “Configuring
Dynamic Interfaces” on page 515.
Before You Configure ATM
■ 21
Chapter 1: Configuring ATM