Juniper ACX1100 Configuration Guide

Automatically Logging Out DHCP Clients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 380
Sending Release Messages When Clients Are Deleted . . . . . . . . . . . . . . . . . . . . . 381
Disabling Automatic Binding of Stray DHCP Requests . . . . . . . . . . . . . . . . . . . . . 381
Using DHCP Relay Agent Option 82 Information . . . . . . . . . . . . . . . . . . . . . . . . . 383
Configuring Option 82 Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384
Including a Prefix in DHCP Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386
Including a Textual Description in DHCP Options . . . . . . . . . . . . . . . . . . . . . 388
Using DHCP Option Information to Selectively Process DHCP Client Traffic . . . 390
Understanding DHCP Option 82 for Protecting Switching Devices Against
Attacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392
DHCP Option 82 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392
Suboption Components of Option 82 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393
Switching Device Configurations That Support Option 82 . . . . . . . . . . . . . . 394
Switching Device, DHCP Clients, and the DHCP Server Are on the Same
VLAN or Bridge Domain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394
Switching Device Acts as a Relay Agent . . . . . . . . . . . . . . . . . . . . . . . . . 394
DHCPv6 Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
Configuring DHCP Option 82 to Help Protect the Switching Devices Against
Attacks (CLI Procedure) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396
Configuring Named Server Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398
Configuring Active Server Groups to Apply a Common DHCP Relay Agent
Configuration to Named Server Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398
Disabling DHCP Relay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399
Part 5 Configuring Protocols on ACX Series Routers
Chapter 12 Configuring Layer 2 Control Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403
Layer 2 Control Protocol on ACX Series Routers . . . . . . . . . . . . . . . . . . . . . . . . . 404
Bridge Priority for Election of Root Bridge and Designated Bridge . . . . . . . . . . . 406
Maximum Age for Awaiting Arrival of Hello BPDUs . . . . . . . . . . . . . . . . . . . . . . . 406
Hello Time for Root Bridge to Transmit Hello BPDUs . . . . . . . . . . . . . . . . . . . . . . 407
Forward Delay Before Ports Transition to Forwarding State . . . . . . . . . . . . . . . . 407
Spanning-Tree Instance Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407
Spanning-Tree Instance Interface Priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408
Spanning-Tree Instance Interface Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408
Spanning-Tree Instance Interface Point-to-Point Link Mode . . . . . . . . . . . . . . . 409
Configuring a Spanning-Tree Instance Interface as an Edge Port for Faster
Convergence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409
Spanning-Tree Protocol Trace Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410
Configuring Rapid Spanning-Tree Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411
Configuring Multiple Spanning-Tree Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
Configuring MST Instances on a Physical Interface . . . . . . . . . . . . . . . . . . . . . . . 415
Disabling MSTP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
Configuring VLAN Spanning-Tree Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
RSTP or VSTP Forced to Run as IEEE 802.1D STP . . . . . . . . . . . . . . . . . . . . . . . . 420
Reverting RSTP or VSTP from Forced IEEE 802.1D STP . . . . . . . . . . . . . . . . . . . 420
Tracing Spanning-Tree Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421
Understanding BPDU Protection for Spanning-Tree Instance Interfaces . . . . . . 423
Configuring BPDU Protection for Spanning-Tree Instance Interfaces . . . . . . . . . 424
Copyright © 2017, Juniper Networks, Inc.xii
ACX Series Universal Access Router Configuration Guide

Juniper ACX1100 Specifications

General

Brand	Juniper
Model	ACX1100
Category	Network Router
Language	English