Admin Guide
Table Of Contents
- Contents
- Chapter 1: Introduction
- Chapter 2: New in this document
- Chapter 3: Basic administration
- Chapter 4: System startup fundamentals
- Chapter 5: Boot parameter configuration using ACLI
- Chapter 6: Run-time process management using ACLI
- Chapter 7: Chassis operations
- Chassis operations fundamentals
- Chassis operations configuration using ACLI
- Enabling jumbo frames
- Configuring port lock
- Configuring SONMP
- Viewing the topology message status
- Associating a port to a VRF instance
- Configuring an IP address for the management port
- Configuring Ethernet ports with Autonegotiation
- Enabling channelization
- Configuring serial management port dropping
- Controlling slot power
- Enabling or disabling the USB port
- Chassis operations configuration using EDM
- Editing system information
- Editing chassis information
- Configuring system flags
- Configuring channelization
- Configuring basic port parameters
- Viewing the boot configuration
- Configuring boot flags
- Enabling Jumbo frames
- Configuring the date and time
- Associating a port to a VRF instance
- Configuring CP Limit
- Configuring an IP address for the management port
- Editing the management port parameters
- Configuring the management port IPv6 interface parameters
- Configuring management port IPv6 addresses
- Auto reactivating the port of the SLPP shutdown
- Editing serial port parameters
- Enabling port lock
- Locking a port
- Viewing power information
- Viewing power status on VSP 8400
- Viewing fan information
- Viewing topology status information
- Viewing the topology message status
- Configuring a forced message control pattern
- Chapter 8: Hardware status using EDM
- Chapter 9: Domain Name Service
- Chapter 10: Licensing
- Chapter 11: Network Time Protocol
- Chapter 12: Secure Shell
- Secure Shell fundamentals
- Secure Shell configuration using ACLI
- Downloading the software
- Enabling the SSHv2 server
- Changing the SSH server authentication mode
- Setting SSH configuration parameters
- Verifying and displaying SSH configuration information
- Connecting to a remote host using the SSH client
- Generating user key files
- Managing an SSL certificate
- Disabling SFTP without disabling SSH
- Enabling SSH rekey
- Configuring SSH rekey data-limit
- Configuring SSH rekey time-interval
- Displaying SSH rekey information
- Downgrading or upgrading from releases that support different key sizes
- Secure Shell configuration using Enterprise Device Manager
- Chapter 13: System access
- System access fundamentals
- System access configuration using ACLI
- Enabling ACLI access levels
- Changing passwords
- Configuring an access policy
- Specifying a name for an access policy
- Allowing a network access to the switch
- Configuring access policies by MAC address
- System access security enhancements
- Displaying the boot config flags status
- Enabling enhanced secure mode
- Creating accounts for different access levels
- Deleting accounts in enhanced secure mode
- Configuring a password for a specific user
- Returning the system to the factory defaults
- Configuring the password complexity rule
- Configuring the password length rule
- Configuring the change interval rule
- Configuring the reuse rule
- Configuring the maximum number of sessions
- Configuring the maximum age rule
- Configuring the pre- and post-notification rule
- System access configuration using EDM
- Chapter 14: ACLI show command reference
- Access, logon names, and passwords
- Basic switch configuration
- Current switch configuration
- CLI settings
- Ftp-access sessions
- Hardware information
- NTP server statistics
- Power summary
- Power information for power supplies
- System information
- System status (detailed)
- Telnet-access sessions
- Users logged on
- Port egress COS queue statistics
- CPU queue statistics
- Chapter 15: Port numbering and MAC address assignment reference
- Chapter 16: Supported standards, RFCs, and MIBs
- Glossary
Chapter 11: Network Time Protocol
The following sections provide information on the Network Time Protocol (NTP).
NTP fundamentals
This section provides conceptual material on the Network Time Protocol (NTP). Review this content
before you make changes to the NTP configuration
Overview
The Network Time Protocol (NTP) synchronizes the internal clocks of various network devices
across large, diverse networks to universal standard time. NTP runs over the User Datagram
Protocol (UDP), which in turn runs over IP. The NTP specification is documented in Request For
Comments (RFC) 1305.
Every network device relies on an internal system clock to maintain accurate time. On local devices,
the internal system clock is usually set by eye or by wristwatch to within a minute or two of the
actual time and is rarely reset at regular intervals. Many local clocks are battery-backed devices that
use room temperature clock oscillators that can drift as much as several seconds each day. NTP
automatically adjusts the time of the devices so that they synchronize within a millisecond (ms) on
LANs and up to a few tens of milliseconds on WANs relative to Coordinated Universal Time (UTC).
The current implementation of NTP supports only unicast client mode. In this mode, the NTP client
sends NTP time requests to other remote time servers in an asynchronous fashion. The NTP client
collects four samples of time from each remote time server. A clock selection algorithm determines
the best server among the selected samples based on stratum, delay, dispersion and the last
updated time of the remote server. The real time clock (RTC) is adjusted to the selected sample
from the chosen server.
NTP terms
A peer is a device that runs NTP software. However, this implementation of NTP refers to peers as
remote time servers that provide time information to other time servers on the network and to the
local NTP client. An NTP client refers to the local network device, the switch, that accepts time
information from other remote time servers.
January 2017 Administering Avaya VSP 7200 Series and 8000 Series 133
Comments on this document? infodev@avaya.com