In what may be the most common client/server model, a client sends an NTP message to one or more
servers and processes the replies as received. The server interchanges addresses and ports, overwrites
certain fields in the message, recalculates the checksum and returns the message immediately.
Information included in the NTP message allows the client to determine the server time regarding local
time and adjust the local clock accordingly. In addition, the message includes information to calculate
the expected timekeeping accuracy and reliability, as well as select the best from possibly several servers.
Following conventions established by the telephone industry [BEL86], the accuracy of each server is
defined by a number called the stratum, with the topmost level (primary servers) assigned as one and
each level downwards (secondary servers) in the hierarchy assigned as one greater than the preceding
level.
Dell Networking OS synchronizes with a time-serving host to get the correct time. You can set Dell
Networking OS to poll specific NTP time-serving hosts for the current time. From those time-serving
hosts, the system chooses one NTP host with which to synchronize and serve as a client to the NTP host.
As soon as a host-client relationship is established, the networking device propagates the time
information throughout its local network.
Protocol Overview
The NTP messages to one or more servers and processes the replies as received. The server interchanges
addresses and ports, fills in or overwrites certain fields in the message, recalculates the checksum, and
returns it immediately.
Information included in the NTP message allows each client/server peer to determine the timekeeping
characteristics of its other peers, including the expected accuracies of their clocks. Using this
information, each peer is able to select the best time from possibly several other clocks, update the local
clock, and estimate its accuracy.
Figure 125. NTP Fields
System Time and Date
1001
Содержание S4820T
Страница 1: ...Dell Configuration Guide for the S4820T System 9 8 0 0 ...
Страница 282: ...Dell 282 Control Plane Policing CoPP ...
Страница 569: ...Figure 62 Inspecting Configuration of LAG 10 on ALPHA Link Aggregation Control Protocol LACP 569 ...
Страница 572: ...Figure 64 Inspecting a LAG Port on BRAVO Using the show interface Command 572 Link Aggregation Control Protocol LACP ...
Страница 573: ...Figure 65 Inspecting LAG 10 Using the show interfaces port channel Command Link Aggregation Control Protocol LACP 573 ...
Страница 617: ...mac address table static multicast mac address vlan vlan id output range interface Microsoft Network Load Balancing 617 ...
Страница 622: ...Figure 81 Configuring Interfaces for MSDP 622 Multicast Source Discovery Protocol MSDP ...
Страница 623: ...Figure 82 Configuring OSPF and BGP for MSDP Multicast Source Discovery Protocol MSDP 623 ...
Страница 624: ...Figure 83 Configuring PIM in Multiple Routing Domains 624 Multicast Source Discovery Protocol MSDP ...
Страница 629: ...Figure 86 MSDP Default Peer Scenario 2 Multicast Source Discovery Protocol MSDP 629 ...
Страница 630: ...Figure 87 MSDP Default Peer Scenario 3 630 Multicast Source Discovery Protocol MSDP ...
Страница 751: ...10 11 5 2 00 00 05 00 02 04 Member Ports Te 1 2 1 PIM Source Specific Mode PIM SSM 751 ...
Страница 905: ...Figure 112 Single and Double Tag First byte TPID Match Service Provider Bridging 905 ...
Страница 979: ...6 Member not present 7 Member not present Stacking 979 ...
Страница 981: ...storm control Storm Control 981 ...
Страница 999: ... Te 1 1 0 INCON Root Rootguard Te 1 2 0 LIS Loopguard Te 1 3 0 EDS Shut Bpduguard Spanning Tree Protocol STP 999 ...
Страница 1103: ...Figure 134 Setup OSPF and Static Routes Virtual Routing and Forwarding VRF 1103 ...