Web Management Guide-R04
Table Of Contents
- How to Use This Guide
- Contents
- Figures
- Tables
- Getting Started
- Web Configuration
- Using the Web Interface
- Basic Management Tasks
- Displaying System Information
- Displaying Hardware/Software Versions
- Configuring Support for Jumbo Frames
- Displaying Bridge Extension Capabilities
- Managing System Files
- Setting the System Clock
- Configuring the Console Port
- Configuring Telnet Settings
- Displaying CPU Utilization
- Configuring CPU Guard
- Displaying Memory Utilization
- Resetting the System
- Interface Configuration
- VLAN Configuration
- Address Table Settings
- Spanning Tree Algorithm
- Congestion Control
- Class of Service
- Layer 2 Queue Settings
- Layer 3/4 Priority Settings
- Setting Priority Processing to IP Precedence/DSCP or CoS
- Mapping Ingress DSCP Values to Internal DSCP Values
- Mapping CoS Priorities to Internal DSCP Values
- Mapping Internal DSCP Values to Egress CoS Values
- Mapping IP Precedence Values to Internal DSCP Values
- Mapping IP Port Priority to Internal DSCP Values
- Quality of Service
- VoIP Traffic Configuration
- Security Measures
- AAA Authentication, Authorization and Accounting
- Configuring User Accounts
- Web Authentication
- Network Access (MAC Address Authentication)
- Configuring HTTPS
- Configuring the Secure Shell
- Access Control Lists
- Filtering IP Addresses for Management Access
- Configuring Port Security
- Configuring 802.1X Port Authentication
- DoS Protection
- DHCPv4 Snooping
- DHCPv6 Snooping
- IPv4 Source Guard
- IPv6 Source Guard
- ARP Inspection
- Application Filter
- Basic Administration Protocols
- Configuring Event Logging
- Link Layer Discovery Protocol
- Simple Network Management Protocol
- Configuring Global Settings for SNMP
- Setting Community Access Strings
- Setting the Local Engine ID
- Specifying a Remote Engine ID
- Setting SNMPv3 Views
- Configuring SNMPv3 Groups
- Configuring Local SNMPv3 Users
- Configuring Remote SNMPv3 Users
- Specifying Trap Managers
- Creating SNMP Notification Logs
- Showing SNMP Statistics
- Remote Monitoring
- Switch Clustering
- Setting a Time Range
- Ethernet Ring Protection Switching
- OAM Configuration
- Connectivity Fault Management
- Configuring Global Settings for CFM
- Configuring Interfaces for CFM
- Configuring CFM Maintenance Domains
- Configuring CFM Maintenance Associations
- Configuring Maintenance End Points
- Configuring Remote Maintenance End Points
- Transmitting Link Trace Messages
- Transmitting Loop Back Messages
- Transmitting Delay-Measure Requests
- Displaying Local MEPs
- Displaying Details for Local MEPs
- Displaying Local MIPs
- Displaying Remote MEPs
- Displaying Details for Remote MEPs
- Displaying the Link Trace Cache
- Displaying Fault Notification Settings
- Displaying Continuity Check Errors
- OAM Configuration
- UDLD Configuration
- LBD Configuration
- Smart Pair Configuration
- Multicast Filtering
- Overview
- Layer 2 IGMP (Snooping and Query for IPv4)
- Configuring IGMP Snooping and Query Parameters
- Specifying Static Interfaces for a Multicast Router
- Assigning Interfaces to Multicast Services
- Setting IGMP Snooping Status per Interface
- Filtering IGMP Query Packets and Multicast Data
- Displaying Multicast Groups Discovered by IGMP Snooping
- Displaying IGMP Snooping Statistics
- Filtering and Throttling IGMP Groups
- MLD Snooping (Snooping and Query for IPv6)
- Multicast VLAN Registration for IPv4
- Multicast VLAN Registration for IPv6
- Basic IP Functions
- IP Configuration
- General IP Routing
- IP Services
- Appendices
- Glossary
Chapter 13
| Basic Administration Protocols
Ethernet Ring Protection Switching
– 484 –
Ethernet rings. An Ethernet ring built using ERPS can provide resilience at a lower
cost and than that provided by SONET or EAPS rings.
ERPS is more economical than EAPS in that only one physical link is required
between each node in the ring. However, since it can tolerate only one break in the
ring, it is not as robust as EAPS. ERPS supports up to 255 nodes in the ring structure.
ERPS requires a higher convergence time when more that 16 nodes are used, but
should always run under than 500 ms.
Operational Concept
Loop avoidance in the ring is achieved by guaranteeing that, at any time, traffic
may flow on all but one of the ring links. This particular link is called the ring
protection link (RPL), and under normal conditions this link is blocked to traffic. One
designated node, the RPL owner, is responsible for blocking traffic over the RPL.
When a ring failure occurs, the RPL owner is responsible for unblocking the RPL,
allowing this link to be used for traffic.
Ring nodes may be in one of two states:
Idle – normal operation, no link/node faults detected in ring
Protection – Protection switching in effect after identifying a signal fault
In Idle state, the physical topology has all nodes connected in a ring. The logical
topology guarantees that all nodes are connected without a loop by blocking the
RPL. Each link is monitored by its two adjacent nodes using Connectivity Fault
Management (CFM) protocol messages.
Protection switching (opening the RPL to traffic) occurs when a signal failure
message generated by the Connectivity Fault Management (CFM) protocol is
declared on one of the ring links, and the detected failure has a higher priority than
any other request; or a Ring – Automatic Protection Switching protocol request (R-
APS, as defined in Y.1731) is received which has a higher priority than any other
local request.
A link/node failure is detected by the nodes adjacent to the failure. These nodes
block the failed link and report the failure to the ring using R-APS (SF) messages.
This message triggers the RPL owner to unblock the RPL, and all nodes to flush their
forwarding database. The ring is now in protection state, but it remains connected
in a logical topology.
When the failed link recovers, the traffic is kept blocked on the nodes adjacent to
the recovered link. The nodes adjacent to the recovered link transmit R-APS (NR - no
request) message indicating they have no local request. When the RPL owner
receives an R-APS (NR) message it starts the Wait-To-Recover (WTR) timer. Once
WTR timer expires, the RPL owner blocks the RPL and transmits an R-APS (NR, RB -
ring blocked) message. Nodes receiving this message flush the forwarding
database and unblock their previously blocked ports. The ring is now returned to
Idle state.