H3C S3600 Series Operation Manual

Page 1

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Table of Contents

Table of Contents

Chapter 1 NTP Configuration.......................................................................................................1-1

1.1 Introduction to NTP............................................................................................................1-1

1.1.1 Applications of NTP................................................................................................. 1-1

1.1.2 Implementation Principle of NTP.............................................................................1-2

1.1.3 NTP Implementation Modes....................................................................................1-4

1.2 Configuring NTP Implementation Modes...........................................................................1-6

1.2.1 Configuration Prerequisites..................................................................................... 1-6

1.2.2 Configuration Procedure......................................................................................... 1-7

1.3 Configuring Access Control Right...................................................................................... 1-9

1.4 Configuring NTP Authentication ........................................................................................ 1-9

1.4.1 Configuration Prerequisites................................................................................... 1-10

1.4.2 Configuration Procedure....................................................................................... 1-10

1.5 Configuring Optional NTP Parameters............................................................................ 1-12

1.6 Displaying and Debugging NTP.......................................................................................1-13

1.7 Configuration Example .................................................................................................... 1-13

1.7.1 Configuring NTP Server Mode..............................................................................1-13

1.7.2 Configuring NTP Peer Mode.................................................................................1-15

1.7.3 Configuring NTP Broadcast Mode........................................................................1-16

1.7.4 Configuring NTP Multicast Mode.......................................................................... 1-19

1.7.5 Configuring NTP Server Mode with Authentication...............................................1-21

Page 2

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

Chapter 1 NTP Configuration

1.1 Introduction to NTP

Network time protocol (NTP) is a time synchronization protocol defined in RFC1305. It is used for time synchronization between a set of distributed time servers and clients. NTP transmits packets through UDP port 123.

NTP is intended for time synchronization between all devices that have clocks in a network so that the clocks of all devices can keep consistent. Thus, the devices can provide multiple unified-time-based applications.

A local system running NTP can not only be synchronized by other clock sources, but also serve as a clock source to synchronize other clocks. Besides, it can synchronize, or be synchronized by other systems by exchanging NTP p ackets.

NTP Configuration

1.1.1 Applications of NTP

NTP is mainly applied to synchronizing the clocks of all devices in a network. For example:

z In network management, the analysis of the log information and debugging

information collected from different devices is meaningful and valid only when network devices that generate the information adopts the same time.

z The billing system requires that the clocks of all network devices be consistent. z Some functions, such as restarting all network devices in a network

simultaneously require that they adopt the same time.

z When multiple systems cooperate to handle a rather complex transaction, they

must adopt the same time to ensure a correct execution order.

z To perform incremental backup operations between a backup server and a host,

you must make sure they adopt the same time.

As setting the system time manually in a network with many devices leads to a lot of workload and cannot ensure the accuracy, it is unfeasible for an administrator to perform the operation. However, an administrator can synchronize the clocks of devices in a network with required accuracy by performing NTP configuration.

NTP has the following advantages:

z Defining the accuracy of clocks by stratum to synchronize the clocks of all devices

in a network quickly

z Supporting access control and MD5 authentication z Sending protocol packets in unicast, multicast, or broadcast mode

1-1

Page 3

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

 Note:

z The clock stratum determines the accuracy, which ranges from 1 to 16. The stratum

of a reference clock ranges from 1 to 15. The clock accuracy decreases as the stratum number increases. A s tratum 16 clock is in the uns ynchronized state and cannot serve as a reference clock.

z The local clock of an S3600 Ethernet switch cannot operate as a reference clock. It

can serve as a NTP server only after synchronized.

1.1.2 Implementation Principle of NTP

Figure 1-1 shows the implementation principle of NTP. Ethernet switch A (LS_A) is connected to Ethernet switch B (LS_B) through Ethernet

ports. Both have their own system clocks, and they need to synchronize the clocks of each other through NTP. To help you to understand the implementation principle, we suppose that:

NTP Configuration

z Before the system clocks of LS_A and LS_B are synchronized, the clock of LS_A

is set to 10:00:00 am, and the clock of LS_B is set to 11:00:00 am.

z LS_B serves as the NTP server, that is, the clock of LS_A will be synchronized to

that of LS_B.

z It takes one second to transfer an NTP packet from LS_A to LS_B or from LS_A to

LS_B.

1-2

Page 4

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

NTP Configuration

NTP packet

NTP Packet

LS_A

NTP Packet received at 10:00:03

NTP Packet received at 10:00:03 am

NTP Packet received at 10:00:03

NTP Packet received at 10:00:03 am

NTP Packet received at 10:00:03

NTP Packet received at 10:00:03 am

NTP Packet received at 10:00:03

NTP packet received at 10:00:03 am

LS_A

10:00:00 am

10:00:00am

NTP packet

NTP Packet

Network

NTP packet 10:00:00 am

NTP Packet10:00:00am

NTP Packet10:00:00 am

NTP Packet10:00:00am

NTP Packet 10:00:00 am

NTP Packet10:00:00am

NTP Packet10:00:00 am

NTP Packet10:00:00am

Network

10:00:00 am11:00:01 am11:00:02 am

10:00:00am 11:00:01am 11:00:02am

10:00:00 am11:00:01 am 11:00:02 am

10:00:00am 11:00:01am 11:00:02am

10:00:00 am11:00:01 am11:00:02 am

10:00:00am 11:00:01am 11:00:02am

10:00:00 am11:00:01 am 11:00:02 am

10:00:00am 11:00:01am 11:00:02am

Network

Figure 1-1 Implementation principle of NTP

LS_B

11:00:01 am

11:00:01am

11:00:01 am

11:00:01am

11:00:01 am

11:00:01am

11:00:01 am

11:00:01am

LSLS_B

LS_B

The procedure of synchronizing the system clock is as follows:

z LS_A sends an NTP packet to LS_B, with a timestamp 10:00:00 am (T

identifying when it is sent.

z When the packet arrives at LS_B, LS_B inserts its own timestamp 11:00:01 am (T

into the packet.

z When the NTP packet leaves LS_B, LS_B inserts its own timestamp 11:00:02 am

) into the packet.

z When receiving a response packet, LS_A inserts a new timestamp 10:00:03 am

) into it.

At this time, LS_A has enough information to calculate the following two parameters:

z Delay for an NTP packet to make a round trip between LS_A and LS_B:

Delay = (T

z Time offset of LS_A relative to LS_B:

Offset = ((T

-T1)-(T3 -T2).

) + (T3 -T4))/2.

2 -T1

LS_A can then set its own clock according to the above information to synchronize its clock to that of LS_B.

For detailed information, refer to RFC1305.

)

1-3

Page 5

Operation Manual – NTP

H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

1.1.3 NTP Implementation Modes

According to the network structure and the position of the local Ethernet switch in the network, the local Ethernet switch can work in multiple NTP modes to synchronize the clock.

I. Client/server mode

NTP Configuration

Client Se

Filters and selects

a clocks and

synchronize the local clock to that of the preferred server

Clock synchronization

request packet

Response packet

Figure 1-2 Client/sever mode

II. Peer mode

Active peer

In peer mode, both

sides can be

synchronized to each

other

Clock synchronization

Network

NetworkNetworkNetwork

NetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetwork

NetworkNetworkNetworkNetworkNetworkNetworkNetworkNetworkNetwork

NetworkNetwork

request packet

Response pac ket

Synchronize

rver

Works in server mode

automatically and send

a response packet

Pas

sive peer

Works in passive pee

mode automatically

Figure 1-3 Peer mod

In the peer mode, the local S3600 Ethernet switch serves as the active peer and sends clock synchronization request packets first, while the remote server serves as the passive peer automatically.

If both of the peers have reference clocks, the one with a smaller stratum number is adopted.

1-4

Page 6

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

III. Broadcast mode

NTP Configuration

Server

Works in the server

mode automatically and

sends response pack ets

Figure 1-4 Broadcast mod

IV. Multicast mode

Server

Works in the server

mode automatically and

sends response pack ets

Network

NetworkNetwork

Broadcasts clock synchronization

packets periodically

Client/server mode request

Response packet

Broadcasts clock synchronization

packets periodically

Network

NetworkNetwork

Multicasts clock synchronization

packets periodically

Client/server mode request

Response packet

Multicasts clock synchronization

packets periodically

Client

Initiates a cl

request after

broadc

Obtains t

client and s

Receives br

Client

Initiates a c

request afte

Obtains t

client and s

Receiv es

he delay between the

the broadc

synchroni

multi

he delay between the

the mult

multicast packets and

synchroni

ient/server mode

receiving the first

ast packet

erver and works in

ast client mode

oadcast packets and zes the local cl ock

lient/server mode r receiving the first cast packet

erver and works in

icast client mode

zes the local clock

Figure 1-5 Multicast mod

Table 1-1 describes ho w the above ment ioned NTP modes are impl emented on S3600 series Ethernet switches.

Table 1-1 NTP implementation modes on S3600 series Ethernet switches

NTP

implementation

Configuration on S3600 series switches

mode

Configure the local S3600 Ethernet switch to operate in the

Client/server mode

NTP server mode. In this mode, the remote server serves as the local time server, while the local switch serves as the client.

Configure the local S3600 switch to operate in NTP peer

Peer mode

mode. In this mode, the remote server serves as the peer of the S3600 switch, and the local switch serves as the active peer.

1-5

Page 7

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

NTP

implementation

Configuration on S3600 series switches

mode

z Configure the local S3600 Ethernet switch to operate in

NTP broadcast server mode. In this mode, the local switch broadcasts NTP packets through the VLAN

Broadcast mode

interface configured on the switch.

z Configure the S3600 switch to operate in NTP broadcast

client mode. In this mode, the local S3600 switch receives broadcast NTP packets through the VLAN interface configured on the switch.

z Configure the local S3600 Ethernet switch to operate in

NTP multicast server mode. In this mode, the local switch sends multicast NTP packets through the VLAN interface

Multicast mode

configured on the switch.

z Configure the local S3600 Ethernet switch to operate in

NTP multicast client mode. In this mode, the local switch receives multicast NTP packets through the VLAN interface configured on the switch.

NTP Configuration

Caution:

An S3600 Ethernet switch can operate in the NTP peer, NTP broadcast server, or NTP multicast server mode only after its clock is synchronized.

1.2 Configuring NTP Implementation Modes

An S3600 Ethernet switch can operate in one of the following NTP modes:

z NTP client mode z NTP server mode z NTP peer mode z NTP broadcast server mode z NTP broadcast client mode z NTP multicast server mode z NTP multicast client mode

1.2.1 Configuration Prerequisites

You need to perform configurations only on the client (or the active peer) when you want an S3600 Ethernet switch to operate in NTP server mode (or NTP peer mode). However, you need to perform configurations on both the server and client when you want the switch to operate in NTP broadcast mode or NTP multicast mode.

1-6

Page 8

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

1.2.2 Configuration Procedure

Table 1-2 Configure NTP implementation modes

Operation Command Description

NTP Configuration

Enter system view

Configure the switch to operate in NTP client mode

Configure the switch to operate in NTP peer mode

Enter VLAN interface view

Configure the switch to operate in the NTP broadcast client mode

system-view

—

ntp-service unicast-server

{ remote-ip | server-name }

[ authentication-keyid

key-id | priority | source-interface

Optional By default, no Ethernet

switch operates in NTP client mode.

Vlan-interface vlan-id | version number ]*

ntp-service unicast-peer { remote-ip |

peer-name } [ authentication-keyid

key-id | priority | source-interface

Optional By default, no Ethernet

switch operates in NTP peer mode.

Vlan-interface vlan-id | version number ]*

interface Vlan-interface vlan-id

—

Optional

ntp-service broadcast-client

By default, no Ethernet switch operates in NTP broadcast client mode.

Configure the switch to operate in NTP broadcast server mode

Configure the switch to operate in NTP multicast client mode

Configure the switch to operate in NTP multicast server mode

ntp-service broadcast-server [ authentication-keyid key-id | version number ]*

ntp-service multicast-client

[ ip-address ]

Optional By default, no Ethernet

switch operates in NTP broadcast server mode.

Optional By default, no Ethernet

switch operates in NTP multicast client mode.

ntp-service multicast-server

[ ip-address ] [ authentication-keyid keyid | ttl ttl-number |

Optional By default, no Ethernet

switch operates in NTP multicast server mode.

version number ]*

1-7

Page 9

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

 Note:

To reduce the risk of being attacked by malicious users against opened socket and enhance switch security, the S3600 series Ethernet switches provide the following functions, so that a socket is opened only when it is needed:

z Opening UDP port 123 (used for NTP) when NTP is enabled; z Close UDP port 123 when NTP is disabled.

The preceding functions are implemented as follows:

z When you enable NTP by using the ntp-service unicast-server, ntp-service

unicast-peer, ntp-service broadcast-client, ntp-service broadcast-server, ntp-service multicast-client, or ntp-service multicast-server command, UDP

port 123 is opened at the same time.

z When you disable NTP from operating in any modes by using the undo forms of the

preceding six commands, UDP port 123 is closed at the same time.

I. NTP client mode

NTP Configuration

z The remote server specified by the remote-ip or server-name argument serves as

the NTP server. The local S3600 Ethernet switch serves as th e client. The clock of the client is synchronized to the NTP server, while the clock of the NTP server is not synchronized to the client.

z The IP address specified by the remote-ip argument cannot be a broadcast

address, a multicast address, or the IP address used by the local reference clock.

II. NTP peer mode

z The remote server specified by the remote-ip or peer-name argument serves as

the peer of the local Ethernet switch, and the local Ethernet switch operates in the active peer mode. The clock of the local switch can be synchronized to the remote server or used to synchronize the clock of the remote serve r.

z The IP address specified by the remote-ip argument cannot be a broadcast

address, a multicast address, or the IP address used by the local reference clock.

III. NTP broadcast server mode

When an S3600 Ethernet switch operates in NTP broadcast server mode, it broadcasts clock synchronization packets periodically. The devices in NTP broadcast client mode will respond to these packets and start the clock synchronization process.

1-8

Page 10

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

IV. NTP multicast server mode

When an S3600 Ethernet switch operates in NTP multicast server mode, it multicasts clock synchronization packets periodically. The devices in the NTP multicast client mode will respond to these packets and start the clock synchronization process. The switch operating in this mode can support up to 1,024 multicast clients.

 Note:

z The total number of the servers and peers configured for a switch is up to 128. z After the configuration, an S3600 Ethernet switch does not establish connections

with peers if it operates in NTP server mode. Whereas if it operates in any of the other modes, it establishes connections with peers.

z If an S3600 Ethernet switch operates in passive peer mode, NTP broadcast client

mode, or NTP multicast client mode, it establishes connections with peers dynamically. If it operates in any of the other modes, it establishes connections with peers statically.

NTP Configuration

1.3 Configuring Access Control Right

The access control right to the NTP server only provides a minimal degree of security measure. A more secure way is to perform identity authentication.

The right of an access request received by the NTP server is matched from the highest to the lowest in order of peer, server, synchronization, and query.

Table 1-3 Configure the access control right to the local NTP server

Operation Command Description

Enter system view

Configure the access control right to the local NTP server

system-view ntp-service access

{ peer | server | synchronization | query } acl-number

1.4 Configuring NTP Authentication

— Optional

By default, the access control right to the local NTP server is peer.

In networks with higher security requirements, the NTP authentication function mu st be enabled to run NTP. Through password authentication on the client and the se rver, the client is synchronized only to the server that passes the authentication. This improves network security.

1-9

Page 11

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

1.4.1 Configuration Prerequisites

NTP authentication configuration involves:

z Configuring NTP authentication on the client z Configuring NTP authentication on the server

Observe the following principles when configuring NTP authentication:

z If the NTP authentication function is not enabled on the client, the client can be

synchronized to a server no matter whether the NTP authentication function is enabled on the server (assuming that other related configurations are perfo rmed).

z You need to couple the NTP authentication with a trusted key. z Configurations on the server and the client must be consistent. z The client with the NTP authentication function enabled is only synchronized to the

server that provides a trusted key.

1.4.2 Configuration Procedure

I. Configuring NTP authentication on the client

NTP Configuration

Table 1-4 Configure NTP authentication on the client

Operation Command Description

Enter system view

Enable the NTP authentication function globally

Configure the NTP authentication key

Configure the specified key to be a trusted key

system-view

ntp-service authentication enable

ntp-service authentication-keyid key-id authentication-model md5

value

ntp-service reliable authentication-keyid key-id

NTP client mode: ntp-service unicast-server

{ remote-ip | server-name }

Associate the

aut

specified key with the corresponding NTP server

Peer mode: ntp-service unicast-peer

{ remote-ip | peer-name }

authentication-keyid key-id

hentication-keyid key-id

— Required

By default, the NTP authentication function is disabled.

Required By default, no NTP

authentication key is configured.

Required By default, no trusted key is

configured.

z In NTP client mode and

NTP peer mode, you need to associate the specified key with the corresponding NTP server on the client.

z You can associate the NTP

server with the authentication key while configuring NTP mode. You can also use this command to associate them after configuring NTP mode.

1-10

Page 12

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

 Note:

z NTP authentication requires that the authentication keys configured for the server

and the client are the same. Besides, the authentication keys must be truste d keys. Otherwise, the client cannot be synchronized with the server.

z In NTP server mode and NTP peer mode, you need to associate the specified key

with the corresponding NTP server (active peer) on the client (passive peer). In these two modes, multiple servers (active peers) may be configured for a client/passive peer, and therefore, the authentication key is required to determine which server the client is synchronized to.

II. Configuring NTP authentication on the server

Table 1-5 Configure NTP authentication on the server

Operation Command Description

NTP Configuration

Enter system view

Enable NTP authentication

system-view

ntp-service authentication enable

ntp-service

Configure an NTP authentication key

authentication-keyid key-id authentication-mode md5

value

Configure the specified key to be a trusted key

Enter VLAN interface view

ntp-service reliable authentication-keyid key-id

interface Vlan-interface vlan-id

Broadcast server mode: ntp-service

broadcast-server authentication-keyid key-id

Associate the specified key with the corresponding NTP server

Multicast server mode:

ntp-service multicast-server authentication-keyid key-id

— Required

By default, the NTP authentication function is disabled.

Required By default, no NTP

authentication key is configured.

Required By default, no trusted

authentication key is configured.

—

z In NTP broadcast server

mode and NTP multicast server mode, you need to associate the specified key with the corresponding NTP server on the server

z You can associate an NTP

server with an authentication key while configuring NTP mode. You can also use this command to associate them after configuring the NTP mode.

1-11

Page 13

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

 Note:

The procedure for configuring NTP authentication on the server is the same a s that on the client. Besides, the client and the server must be configured with the same authentication key.

1.5 Configuring Optional NTP Parameters

Optional NTP parameters are:

z Local VLAN interface that sends NTP packets z Number of dynamic sessions that can be established locally z VLAN interface disabled from receiving NTP packets

Table 1-6 Configure optional NTP parameters

Operation Command Description

NTP Configuration

Enter system view Configure a local

interface that sends NTP packets

Configure the number of sessions that can be established locally

Enter VLAN interface view

Disable an interface from receiving NTP packets

system-view ntp-service

source-interface Vlan-interface vlan-id

ntp-service max-dynamic-sessions

number

interface Vlan-interface vlan-id

ntp-service in-interface disable

—

Optional

Optional By default, up to 100 dynamic

sessions can be established locally.

—

Optional By default, a VLAN interface

receives NTP packets.

Caution:

z If a sending interface is specified in the ntp-service unicast-server command or

the ntp-serv ice unicast-peer command, the source IP address of an NTP packet is the address of this interface.

z Dynamic connections can be established when a switch operates in passive peer

mode, NTP broadcast client mode, or NTP multicast client mode. In other modes, the connections established are static.

1-12

Page 14

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

1.6 Displaying and Debugging NTP

After the above configurations, you can execute display commands in any view to display the running status of switch, and verify the effect of the configurations.

Table 1-7 Display and debug NTP

Operation Command Description

NTP Configuration

Display the status of NTP services Display the information about the

sessions maintained by NTP Display the brief information about

NTP servers along the path from the local device to the reference clock source

1.7 Configuration Example

1.7.1 Configuring NTP Server Mode

I. Network requirements

The local clock of H3C1 is set to the NTP master clock, with a stratum level of 2.

 Note:

H3C1 is a switch that allows the local clock to serve as the NTP master clock.

display ntp-service status display ntp-service

sessions [ verbose ]

display ntp-service trace

The display commands can be executed in any view

An S3600 Ethernet switch considers H3C1 as the NTP server and operates in client mode, while H3C1 operates in server mode automatically.

II. Network diagram

12/24

1.0.1.

1.0.1.11/24

1.0.1.11/24 S3600

H3C1

Figure 1-6 Network diagram for the NTP server mode configuration

S3600

III. Configuration procedure

Perform the following configurations on the S3600 switch. # View the NTP status of the S3600 switch before synchronization.

1-13

Page 15

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

<S3600> display ntp-service status Clock status: unsynchronized Clock stratum: 16 Reference clock ID: none Nominal frequency: 60.0002 Hz Actual frequency: 60.0002 Hz Clock precision: 2^18 Clock offset: 0.0000 ms Root delay: 0.00 ms Root dispersion: 0.00 ms Peer dispersion: 0.00 ms Reference time: 00:00:00.000 UTC Jan 1 1900 (00000000.00000000)

# Set H3C1 to the NTP server of the S3600 switch.

<S3600> system-view [S3600] ntp-service unicast-server 1.0.1.11

# (After the above configurations, the S3600 switch is synchronized to H3C1.) V iew the NTP status of the S3600 switch.

NTP Configuration

[S3600] display ntp-service status Clock status: synchronized Clock stratum: 3 Reference clock ID: 1.0.1.11 Nominal frequency: 60.0002 Hz Actual frequency: 60.0002 Hz Clock precision: 2^18 Clock offset: 0.0000 ms Root delay: 9.54 ms Root dispersion: 26.42 ms Peer dispersion: 10.96 ms Reference time: 07:05:43.263 UTC Apr 25 2006(C7F848C7.438348F5)

The above output information indicates that the S3600 switch is synchronized to H3C1, and the stratum level of its clock is 3, one level lower than that of H3C1.

# View the information about NTP sessions of the S3600 switch. (You can see that the S3600 switch establishes a connection with H3C1.)

[S3600] display ntp-service sessions source reference stra reach poll now offset delay disper ************************************************************************** [12345]1.0.1.11 127.127.1.0 2 255 64 39 0.0 9.5 5.1 note: 1 source(master),2 source(peer),3 selected,4 candidate,5 configured

1-14

Page 16

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

1.7.2 Configuring NTP Peer Mode

I. Network requirements

The local clock of H3C2 is set to the NTP maste r clock, with the clock strat um level of 2. An S3600 Ethernet switch considers H3C2 as the NTP server a nd serves as the client,

while H3C2 operates in server mode automatically. In addition, H3C3 considers the S3600 Ethernet switch as its peer.

 Note:

This example assumes that:

z H3C2 is a switch that allows its local clock to be the mast er clock. z H3C3 is a switch that allows its local clock to be the master clock and the stratum

level of its clock is 1.

NTP Configuration

II. Network diagram

H3 C 2

3.0.1.

31/24

3.0.1.32/24

H3 C 3

3.0.1.32/24

S3600

3.0.1.33/24

Figure 1-7 Network diagram for NTP peer mode configuration

III. Configuration procedure

1) Configure the S3600 series switch. # Set H3C2 to the NTP server.

<S3600> system-view [S3600] ntp-service unicast-server 3.0.1.31

2) Configure H3C3 (after the S3600 Ethernet switch is synchronized to H3C2). # Enter system view.

<H3C3> system-view [H3C3]

# Set the S3600 Ethernet switch to the peer of H3C3.

1-15

Page 17

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

[H3C3] ntp-service unicast-peer 3.0.1.33

The S3600 Ethernet switch and H3C3 are a pair of peers. H3C3 operates in active peer mode, while the S3600 Ethernet switch operates in passive peer mode. Because the stratum level of the local clock of H3C3 is 1, and that of the S3600 Ethernet swit ch is 3, the S3600 Ethernet switch is synchronized to H3C3.

View the status of the S3600 Ethernet switch after synchronization.

[S3600] display ntp-service status Clock status: synchronized Clock stratum: 2 Reference clock ID: 3.0.1.32 Nominal frequency: 60.0002 Hz Actual frequency: 60.0002 Hz Clock precision: 2^18 Clock offset: 0.0000 ms Root delay: 31.28 ms Root dispersion: 0.08 ms Peer dispersion: 27.31 ms Reference time: 07:07:59.823 UTC Apr 25 2006(C7F8494F.D2E568A5)

NTP Configuration

The output information indicates that the S3600 Ethernet switch is synchronized to H3C3 and the stratum level of its local clock is 2, one level lower than that H3C3.

# View the information about the NTP sessions of the S3600 Ethernet switch (you can see that a connection is established between the S3600 Ethernet switch and H3C3).

[S3600] display ntp-service sessions source reference stra reach poll now offset delay disper ************************************************************************** [2]3.0.1.32 LOCL 1 14 64 60 -1.0 0.0 1.6 note: 1 source(master),2 source(peer),3 selected,4 candidate,5 configured

1.7.3 Configuring NTP Broadcast Mode

I. Network requirements

The local clock of H3C3 is set to the NTP master clock, with a stratum level of 2. NTP packets are broadcast through Vlan-interface2.

Configure S3600-1 and S3600-2 to listen to broadcast packets through their own Vlan-interface2.

1-16

Page 18

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

 Note:

This example assumes that H3C3 is a switch that supports the local clock being the master clock.

II. Network diagram

3.0.1.31/24

3.0.1.31/24 rface 2

rface 2

Vlan-inte

1.0.1.31/24

Vlan

-interface 2

S3600-2 H3C 4

-interface 2

Vlan-inte

3.0.1.32/24

rface 2

H3C 3

S3600-1

NTP Configuration

Figure 1-8 Network diagram for the NTP broadcast mode configuration

III. Configuration procedure

1) Configure H3C3. # Enter system view.

<H3C3> system-view [H3C3]

# Enter Vlan-interface2 view.

[H3C3] interface Vlan-interface 2 [H3C3-Vlan-interface2]

# Set H3C3 to the broadcast server, which sends broadcast packets through Vlan-interface2.

[H3C3-Vlan-interface2] ntp-service broadcast-server

2) Configure S3600-1. # Enter system view.

<S3600-1> system-view [S3600-1]

# Enter Vlan-interface2 view.

[S3600-1] interface Vlan-interface 2 [S3600-1-Vlan-interface2]

# Set S3600-1 to a broadcast client.

[S3600-1-Vlan-interface2] ntp-service broadcast-client

1-17

Page 19

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

3) Configure S3600-2 # Enter system view.

<S3600-2> system-view [S3600-2]

# Enter Vlan-interface2 view.

[S3600-2] interface Vlan-interface 2 [S3600-2-Vlan-interface2]

# Set S3600-2 to a broadcast client.

[S3600-2-Vlan-interface2] ntp-service broadcast-client

After the above configurations, S3600-1 and S3600-2 will listen to broadcast packets through their own Vlan-interface2, and H3C3 will send broadcast packets through Vlan-interface2. Because S3600-2 and H3C3 do not share th e same network segment, S3600-2 cannot receive broadcast packets from H3C3, while S3600-1 is syn chronized to H3C3 after receiving broadcast packets from H3C3.

View the status of S3600-1 after synch r onization.

NTP Configuration

[S3600-1] display ntp-service status Clock status: synchronized Clock stratum: 3 Reference clock ID: 3.0.1.31 Nominal frequency: 60.0002 Hz Actual frequency: 60.0002 Hz Clock precision: 2^18 Clock offset: -9.1060 ms Root delay: 15.84 ms Root dispersion: 3.52 ms Peer dispersion: 29.62 ms Reference time: 07:15:14.403 UTC Apr 25 2006(C7F84B02.6735F3D7)

The output information indicates that S3600-1 is synchronized to H3C3, with the clock stratum level of 3, one level lower than that of H3C3.

# View the information about the NTP sessions of S3600-1 and you can see that a connection is established between S3600-1 and H3C3.

[S3600-1] display ntp-service sessions source reference stra reach poll now offset delay disper ************************************************************************** [1]3.0.1.31 127.127.1.0 2 14 64 60 -1.0 0.0 1.6 note: 1 source(master),2 source(peer),3 selected,4 candidate,5 configured

1-18

Page 20

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

1.7.4 Configuring NTP Multicast Mode

I. Network requirements

The local clock of H3C3 is set to the NTP master clock, with a clock stratum level of 2. H3C3 advertises multicast packets th rough Vlan-interface2.

S3600-1 and S3600-2 respectively listen to multicast packets through their own Vlan-interface2.

 Note:

This example assumes that H3C3 is a switch that supports the local clock being the master clock.

II. Network diagram

NTP Configuration

3.0.1.31/24

Vlan-inte

rface 2

1.0.1.31/24

-interface 2

Vlan

S3600-2 H3C 4

Vlan-inte

rface 2

3.0.1.32/24

rface 2

H3C 3

S3600-1

Figure 1-9 Network diagram for NTP multicast mode configuration

III. Configuration procedure

1) Configure H3C3. # Enter system view.

<H3C3> system-view [H3C3]

# Enter VLAN-interface2 view.

[H3C3] interface Vlan-interface 2

# Set H3C3 to a multicast server.

[H3C3-Vlan-interface2] ntp-service multicast-server

2) Configure S3600-1. # Enter system view.

<S3600-1> system-view

1-19

Page 21

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

[S3600-1]

# Enter Vlan-interface2 view.

[S3600-1] interface Vlan-interface 2

# Set S3600-1 to a multicast client.

[S3600-1-Vlan-interface2] ntp-service multicast-client

3) Configure S3600-2. # Enter system view.

<S3600-2> system-view [S3600-2]

# Enter Vlan-interface2 view.

[S3600-2] interface Vlan-interface 2

# Set S3600-2 to a multicast client.

[S3600-2-Vlan-interface2] ntp-service multicast-client

After the above configurations, S3600-1 and S3600-2 respectively listen to multicast packets through their own Vlan-interface2, and H3C3 advertises multicast packets through Vlan-interface2. Because S3600-2 and S3600-3 do not share the same network segment, S3600-2 cannot receive multicast packets from H3C3, while S3600-1 is synchronized to H3C3 after receiving multicast packets from H3C3.

NTP Configuration

View the status of S3600-1 after synch r onization.

[S3600-1] display ntp-service status Clock status: synchronized Clock stratum: 3 Reference clock ID: 3.0.1.31 Nominal frequency: 60.0002 Hz Actual frequency: 60.0002 Hz Clock precision: 2^18 Clock offset: 0.0000 ms Root delay: 63.21 ms Root dispersion: 0.30 ms Peer dispersion: 46.13 ms Reference time: 07:18:32.952 UTC Apr 25 2006(C7F84BC8.F3BBD7B2)

The output information indicates that S3600-1 is synchronized to H3C3, with a clock stratum level of 3, one stratum level lower than that H3C3.

# View the information about the NTP sessions of S3600-1 (You can see that a connection is established between S3600-1 and H3C3).

[S3600-1] display ntp-service sessions source reference stra reach poll now offset delay disper **************************************************************************

1-20

Page 22

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

[1]3.0.1.31 127.127.1.0 2 1 64 20 0.0 15.4 0.0 note: 1 source(master),2 source(peer),3 selected,4 candidate,5 configured

1.7.5 Configuring NTP Server Mode with Authentication

I. Network requirements

The local clock of H3C1 is set to the NTP master clock, with a clock stratum level of 2. An S3600 Ethernet switch considers H3C1 as the NTP server and operates in client

mode, while H3C1 operates in server mode automatically. In addition, the NTP authentication function is enabled on both sides.

 Note:

This example assumes that H3C1 is a switch that supports the local clock being the NTP master clock.

NTP Configuration

II. Network diagram

1.0.1.

12/24

1.0.1.11/24

1.0.1.11/24 S3600

H3C1

S3600

Figure 1-10 Network diagram for NTP se rver mode with authentication configuration

III. Configuration procedure

1) Configure the S3600 Ethernet switch. # Enter system view.

<S3600> system-view [S3600]

# Set H3C1 to the NTP server.

[S3600] ntp-service unicast-server 1.0.1.11

# Enable the NTP authentication function.

[S3600] ntp-service authentication enable

# Configure an MD5 authentication key, with the key ID being 42 and the key being aNiceKey.

[S3600] ntp-service authentication-keyid 42 authentication-mode md5 aNiceKey

# Specify the key as a trusted key.

[S3600] ntp-service reliable authentication-keyid 42

1-21

Page 23

Operation Manual – NTP H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

[S3600] ntp-service unicast-server 1.0.1.11 authentication-keyid 42

After the above configurations, S3600 is ready to synchronize with H3C1. Because the NTP authentication function is not enabled on H3C1, S3600 will fail to be synchronized to H3C1.

To synchronize the S3600 Ethernet switch, you need to perform the following configurations on H3C1.

# Enable the NTP authentication function on H3C1.

[H3C1] system-view [H3C1] ntp-service authentication enable

# Configure an MD5 authentication key, with the key ID being 42 and the key being aNiceKey.

[H3C1] ntp-service authentication-keyid 42 authentication-mode md5 aNiceKey

# Specify the key as a trusted key.

[H3C1] ntp-service reliable authentication-keyid 42

(After the above configurations, the S3600 Ethernet switch can be synchronized to H3C1.) View the status of S3600 after synchronization.

NTP Configuration

The output information indicates that S3600 is synchronized to H3C1, with a clock stratum level of 3, one stratum level lower than that H3C1.

# View the information about NTP sessions of S3600 (You can see that a connection is established between S3600 and H3C1).

<S3600> display ntp-service sessions source reference stra reach poll now offset delay disper ************************************************************************** [5]1.0.1.11 127.127.1.0 2 255 64 39 0.0 9.5 5.1 note: 1 source(master),2 source(peer),3 selected,4 candidate,5 configured

1-22