Huawei Quidway S3000-EI Series User manual

Operation Manual - Network Protocol
Quidway S3000-EI Series Ethernet Switches Table of Contents
Huawei Technologies Proprietary
i
Table of Contents
Chapter 1 ARP Configuration.......................................................................................................1-1
1.1 Introduction to ARP............................................................................................................1-1
1.2 Configure ARP...................................................................................................................1-2
1.2.1 Manually Add/Delete Static ARP Mapping Entries .................................................1-2
1.2.2 Configure the Dynamic ARP Aging Timer............................................................... 1-2
1.2.3 Enabling/Disabling ARP the Checking Function of ARP Entry...............................1-3
1.3 Gratuitous ARP Configuration ...........................................................................................1-3
1.3.1 Gratuitous ARP Overview....................................................................................... 1-3
1.3.2 Configuration Tasks................................................................................................1-4
1.3.3 Configuration Example............................................................................................1-4
1.4 Display and debug ARP.....................................................................................................1-4
Chapter 2 DHCP-Snooping Configuration.................................................................................. 2-1
2.1 DHCP-Snooping Overview................................................................................................2-1
2.2 Configure DHCP-Snooping................................................................................................2-1
2.2.1 Enable/Disable the DHCP-Snooping Function of the Switch..................................2-1
2.2.2 Setting the Port as Trusted Port..............................................................................2-2
2.3 Display and debug DHCP-Snooping .................................................................................2-2
Chapter 3 DHCP Client Configuration......................................................................................... 3-1
3.1 Overview of DHCP Client ..................................................................................................3-1
3.2 DHCP Client Configuration................................................................................................3-2
3.2.1 Configuring a VLAN Interface to Obtain IP Address Using DHCP .........................3-2
3.3 Displaying and Debugging DHCP Client Configuration.....................................................3-3
Chapter 4 BOOTP Client Configuration ......................................................................................4-1
4.1 Overview of BOOTP Client................................................................................................4-1
4.2 BOOTP Client Configuration.............................................................................................. 4-1
4.2.1 Configuring a VLAN Interface to Obtain the IP Address Using BOOTP................. 4-1
4.3 Displaying and Debugging BOOTP Client.........................................................................4-2
Chapter 5 Access Management Configuration ..........................................................................5-1
5.1 Access Management Overview......................................................................................... 5-1
5.2 Configure Access Management.........................................................................................5-1
5.2.1 Enable Access Management Function ...................................................................5-2
5.2.2 Configure Layer 2 Isolation between Ports.............................................................5-2
5.2.3 Configure Port, IP Address and MAC Address Binding..........................................5-2
5.3 Display and debug Access Management.......................................................................... 5-3
5.4 Access Management Configuration Example....................................................................5-4

Operation Manual - Network Protocol
Quidway S3000-EI Series Ethernet Switches Table of Contents
Huawei Technologies Proprietary
ii
Chapter 6 IP Performance Configuration.................................................................................... 6-1
6.1 IP Performance Configuration ...........................................................................................6-1
6.1.1 Configure TCP Attributes........................................................................................ 6-1
6.2 Display and debug IP Performance...................................................................................6-2
6.3 Troubleshoot IP Performance............................................................................................ 6-2

Operation Manual - Network Protocol
Quidway S3000-EI Series Ethernet Switches Chapter 1 ARP Configuration
Huawei Technologies Proprietary
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Chapter 1 ARP Configuration
1.1 Introduction to ARP
I. Necessity of ARP
An IP address cannot be directly used for communication between network devices
because network devices can only identify MAC addresses. An IP address is only an
address of a host in the network layer. To send the data packets transmitted through the
network layer to the destination host, physical address of the host is required. So the IP
address must be resolved into a physical address.
II. ARP implementation procedure
When two hosts on the Ethernet communicate, they must know the MAC addresses of
each other. Every host will maintain the IP-MAC address translation table, which is
known as ARP mapping table. A series of maps between IP addresses and MAC
addresses of other hosts which were recently used to communicate with the local host
are stored in the ARPmapping table. When a dynamicARP mapping entry is not in use
for a specified period of time, the host will remove it from the ARP mapping table so as
to save the memory space and shorten the interval for switch to search ARP mapping
table.
Suppose there are two hosts on the same network segment: HostAand Host B. The IP
address of Host A is IP_A and the IP address of Host B is IP_B. Host A will transmit
messages to Host B. Host A checks its own ARP mapping table first to make sure
whether there are correspondingARP entries of IP_B in the table. If the corresponding
MAC address is detected, Host A will use the MAC address in the ARP mapping table
to encapsulate the IP packet in frame and send it to Host B. If the corresponding MAC
address is not detected, Host A will store the IP packet in the queue waiting for
transmission, and broadcast it throughout the Ethernet. The ARP request packet
contains the IP address of Host B and IP address and MAC address of Host A. Since
the ARPrequest packet is broadcast, all hosts on the network segment can receive the
request. However, only the requested host (i.e., Host B) needs to process the request.
Host B will first store the IP address and the MAC address of the request sender (Host
A) in the ARP request packet in its own ARP mapping table. Then Host B will generate
an ARP reply packet into which, it will add MAC address of Host B, and then send it to
Host A. The reply packet will be directly sent to Host A in stead of being broadcast.
Receiving the reply packet, Host A will extract the IP address and the corresponding
MAC address of Host B and add them to its own ARP mapping table. Then Host A will
send Host B all the packets standing in the queue.

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Quidway S3000-EI Series Ethernet Switches Chapter 1 ARP Configuration
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Normally, dynamic ARP executes and automatically searches for the resolution from
the IP address to the Ethernet MAC address without the administrator.
1.2 Configure ARP
The ARP mapping table can be maintained dynamically or manually. Usually, the
manually configured mapping from the IP addresses to the MAC addresses is known
as staticARP. The user can display, add or delete the entries in the ARP mapping table
through relevant manual maintenance commands.
The staticARP configuration includes:
zManually Add/delete static ARP Mapping Entries
zConfigure the dynamic ARP aging timer
zEnabling/Disabling ARP the Checking Function of ARP Entry
1.2.1 Manually Add/Delete Static ARP Mapping Entries
Perform the following configuration in System view.
Table 1-1 Manually add/delete static ARP mapping Entries
Operation Command
Manually add a static ARP mapping
entry
arp static ip-address mac-address
[ vlan-id { interface-type
interface-number | interface-name } ]
Manually delete a static ARP mapping
entry undo arp ip-address
Static ARP map entry will be always valid as long as Ethernet switch works normally.
But if the VLAN corresponding ARP mapping entry is deleted, the ARP mapping entry
will be also deleted. The valid period of dynamic ARP map entries will last only 20
minutes by default.
The parameter vlan-id must be the ID of a VLAN thathas been created by the user, and
the Ethernet port specified behind this parameter must belong to the VLAN.
By default, the ARP mapping table is empty and the address mapping is obtained
through dynamic ARP.
1.2.2 Configure the Dynamic ARP Aging Timer
For purpose of flexible configuration, the system provides the following commands to
assign dynamic ARP aging period. When the system learns a dynamic ARP entry, its
aging period is based on the current value configured.
Perform the following configuration in system view.

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Quidway S3000-EI Series Ethernet Switches Chapter 1 ARP Configuration
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Table 1-2 Configure the dynamic ARP aging timer
Operation Command
Configure the dynamic ARP aging timer arp timer aging aging-time
restore the default dynamic ARP aging time undo arp timer aging
By default, the aging time of dynamic ARP aging timer is 20 minutes.
1.2.3 Enabling/Disabling ARP the Checking Function of ARP Entry
You can use the following command to control the device whether to learn the ARP
entry where the MAC address is multicast MAC address.
Perform the following configuration in system view.
Table 1-3 Enabling/Disabling ARP the checking function of ARP entry
Operation Command
Enable the checking of ARP entry, that is, the device
does not learn the ARP entry where the MAC address is
multicast MAC address arp check enable
Disable the checking of ARP entry, that is, the device
learns the ARP entry where the MAC address is
multicast MAC address undo arp check enable
By default, the checking of ARP entry is enabled, that is, the device does not learn the
ARP entry where the MAC address is multicast MAC address.
1.3 Gratuitous ARP Configuration
1.3.1 Gratuitous ARP Overview
Gratuitous ARP function is to implement the following functions by sending out
gratuitous ARP packets:
zBy sending gratuitous ARPpackets, network devices can figure out whether the IP
addresses of other devices conflict with that of its own.
zIf the device which sends the gratuitous ARP packet changed its hardware
address (probably, it turns off, has its interface card changed, and then reboots),
this packet can make old hardware address in the cache of other devices update
accordingly. For example, when a device receives a gratuitous ARP request
existing in the cache of the device from an IP address, then the sending hardware
address (such as Ethernet address) in the gratuitous ARP request needs to
update the content in the cache. The above operation must be done when a
device receives any gratuitous ARP request. ARP request is broadcast on the

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Quidway S3000-EI Series Ethernet Switches Chapter 1 ARP Configuration
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network, so all hosts on the network must do this every time the ARP request is
sent.
Characteristics of gratuitousARP packets:
zThe source and destination IP addresses are all native addresses, and the source
MAC address of the packet is native MAC address.
zIf another device receives a gratuitous ARP packet and finds out that the IP
address in the ARP packet conflicts with that of its own, it sends an ARP reply
back to the device sending the ARP packet.
1.3.2 Configuration Tasks
The configuration tasks of the gratuitous ARP are described in the following table:
Table 1-4 Configure gratuitous ARP
Sequence
number Configuration item Command Description
1 Enter system
view <Quidway> system-view —
2 Enable ARP
packet learning [Quidway]
gratuitous-arp-learning enable Required
Use the corresponding undo command to cancel the configuration.
1.3.3 Configuration Example
I. Network requirements
Enable gratuitous ARP packet learning on the switch QuidwayA.
II. Configuration procedure
<QuidwayA> system-view
[QuidwayA] gratuitous-arp-learning enable
1.4 Display and debug ARP
After the above configuration, execute display command in any view to display the
running of the ARP configuration, and to verify the effect of the configuration. Execute
debugging command in user view to debug ARP configuration. Execute reset
command in user view to clearARP mapping table.

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Table 1-5 Display and debug ARP
Operation Command
Display ARP mapping table display arp [ static | dynamic | ip-address ]
Display the current setting of the
dynamic ARP map aging timer display arp timer aging
Reset ARP mapping table reset arp [ dynamic | static |interface { interface-type interface-number |
interface-name }]
Enable ARP information
debugging debugging arp packet
Disable ARP information
debugging undo debugging arp packet

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Quidway S3000-EI Series Ethernet Switches Chapter 2 DHCP-Snooping Configuration
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Chapter 2 DHCP-Snooping Configuration
2.1 DHCP-Snooping Overview
For security, the IP addresses used by online users may be recorded to confirm the
association between the users’ IP addresses and their MAC addresses. The Layer 3
Ethernet switch records the IP addresses obtained by the clients with DHCP Relay,
while the Layer 2 Ethernet switch listens to the DHCP broadcast packets for this
purpose.
To assign IP addresses to the clients, DHCP server transmits DHCPACK packets.After
received the packets, theclient can obtain an IPaddress. Snooping DHCPACK is a way
to know the clients’ IP addresses.
The client broadcasts DHCPREQUEST packet to request DHCP server to assign
address. The IP address requested through DHCPREQUEST is the same as that
assigned through DHCPACK. So snooping DHCPREQUEST is another way to know
clients’ IP addresses.
With DHCP-Snooping enabled, the switch can distract IP address and MAC address
from the DHCPACK or DHCPREQUEST packets received and record them.
In addition, pseudo-DHCP servers in the network may cause users to get incorrect IP
addresses. To guarantee that users can obtain IP address from the legal DHCP servers,
DHCP-Snooping allows ports to be set as trusted or distrusted. The former ports
connect DHCP servers or other switches and the latter ports connect users or network.
Distrusted ports discard the DHCPACK and DHCPOFF packets from DHCP servers,
whereas trusted ports forward these types of packets. In this way, users can get correct
IP address.
2.2 Configure DHCP-Snooping
DHCP-Snooping configuration includes:
zEnable/Disable the DHCP-Snooping function of the Switch
zSetting the port as trusted port
2.2.1 Enable/Disable the DHCP-Snooping Function of the Switch
Perform the following configuration in System view.

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Table 2-1 Enable/Disable the DHCP-Snooping function of the switch
Operation Command
Enable the DHCP-Snooping function of the switch dhcp-snooping
Disable the DHCP-Snooping function of the switch undo dhcp-snooping
By default, the switch does not enable DHCP-Snooping function.
2.2.2 Setting the Port as Trusted Port
Perform the following configuration in Ethernet port view.
Table 2-2 Setting the port as trusted port
Operation Command
Set the port as trusted port dhcp-snooping trust
Restore the port as distrusted port undo dhcp-snooping trust
By default, the ports of a switch are distrusted port.
2.3 Display and debug DHCP-Snooping
After the above configuration, execute display command in any view to display the
clients’ IP address and MAC address bindings recorded through DHCP-Snooping.
Table 2-3 Display and debug DHCP-Snooping
Operation Command
Display the information of the
DHCP-Snooping correspondence table display dhcp-snooping [ vlan { vlan_list | all } ]
Display the number of the DHCP-Snooping
entries in the binding table display dhcp-snooping count
Display the status of DHCP-Snooping
function and the information of trusted ports display dhcp-snooping trust

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Quidway S3000-EI Series Ethernet Switches Chapter 3 DHCP Client Configuration
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Chapter 3 DHCP Client Configuration
3.1 Overview of DHCP Client
With expansion of network size and complication of network structure, network
configuration becomes more and more complex. It is often the case that computers
change physical positions frequently (portable computers and wireless networks for
example) and that computers exceed the IP addresses available. Dynamic host
configuration protocol (DHCP) has been developed right for this situation. DHCP is in
client/server structure, with DHCP client dynamic requesting configuration information,
while DHCP server returning configuration information base on the specific policies.
A typical DHCP application often contains a DHCP server and several clients (desktop
and laptop PCs). See the following figure.
LAN
DHCP Server
DHCP Client DHCP Client
DHCP Client DHCP Client
Figure 3-1 Typical DHCP application
To obtain valid dynamic IP addresses, DHCP client exchanges different types of
information with the server at different stages. One of the following three situations may
occur:
1) DHCP client logs into the network for the first time
When DHCP client logs into the network for the first time, its communication with the
DHCP server includes these four stages:
zDiscover stage, the stage when the DHCP client looks for the DHCP server. The
client broadcasts the DHCP_Discover message and only the DHCP server can
respond.
zOffer stage, the stage when the DHCP server allocates the IP address. After
receiving the DHCP_Discover message from the client, the DHCP server chooses
an IP address still available in IP address pool for the client, and sends to the client
the DHCP_Offer message containing the leased IP address and other settings.
zSelect stage, the stage when the client selects the IP address. If several DHCP
servers send DHCP_Offer messages to the client, the client only accepts the first