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OLT Network Configuration, Cisco Catalyst PON Series Switches

The documentation set for this product strives to use bias-free language. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. Learn more about how Cisco is using Inclusive Language.

• Configuring MAC Address Table
• Configuring DLF Forwarding
• Configuring Port Mirroring
• Configuring Spanning Tree Protocol
• Configuring IP Addresses
• Configuring IPv6 Addresses
• Configuring Address Resolution Protocol
• Configuring SNMP
• Configuring DHCP Snooping
• Configuring DHCPv6 Snooping
• Configuring Static Routing
• Configuring LLDP

Book Title

OLT Network Configuration, Cisco Catalyst PON Series Switches

Configuring MAC Address Table

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Chapter: Configuring MAC Address Table

Configuring MAC Address Table

Configuring the MAC Address Table

The MAC address table contains address information that the device uses to forward traffic between ports. The address table lists the destination MAC address, the associated VLAN ID, and port number associated with the address and the type (static or dynamic). When a packet enters the device the device looks up the MAC address table for the destination MAC address and the VLAN ID of the packet. If the address is found the device forwards the packet to the specified ports. If the address is not found the device boradcasts the packet in the VLAN.

The system is able to learn MAC addresses. If the MAC address of a received packet does not exist in the MAC address table, the system will add the source MAC address, VLAN ID, and port number of the received packet as a new entry to the MAC address table.

You can also manually configure the MAC address entris. You can configure the MAC address table based on the actual network condition, that is, the administrator can add or modify static entries, permanent entries, blackhole entries, dynamic entries.

You can configure the MAC address aging function to remove the MAC address after a specified time. If a device does not send any packets for a certain period of time, the system deletes the MAC address entries associated with the device. MAC address aging can be used only on learned MAC addresses or dynamic MAC addresses.

How to Configure MAC Address Table

Configuring Aging Time for MAC Address Table

To configure the Aging Time for MAC Address Table, perform this procedure:

Procedure

Example:

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Configuring the MAC Address Table

The documentation set for this product strives to use bias-free language. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. Learn more about how Cisco is using Inclusive Language.

Configuring the MAC Address Table

All Ethernet interfaces on Cisco Nexus 3000 Series switches maintain media access control (MAC) address tables. This chapter describes the configuration of the MAC address tables. It includes the following sections:

Information About MAC Addresses

To switch frames between LAN ports, the switch maintains an address table. When the switch receives a frame, it associates the media access control (MAcC) address of the sending network device with the LAN port on which it was received.

The switch dynamically builds the address table by using the MAC source address of the frames received. When the switch receives a frame for a MAC destination address not listed in its address table, it floods the frame to all LAN ports of the same VLAN except the port that received the frame. When the destination station replies, the switch adds its relevant MAC source address and port ID to the address table. The switch then forwards subsequent frames to a single LAN port without flooding all LAN ports.

You can also enter a MAC address, which is termed a static MAC address, into the table. These static MAC entries are retained across a reboot of the switch.

In addition, you can enter a multicast address as a statically configured MAC address. A multicast address can accept more than one interface as its destination.

The address table can store a number of unicast and multicast address entries without flooding any frames. The switch uses an aging mechanism, defined by a configurable aging timer, so if an address remains inactive for a specified number of seconds, it is removed from the address table.

Configuring MAC Addresses

Configuring a Static MAC Address

You can configure MAC addresses for the switch. These addresses are static MAC addresses.

Note	You can also configure a static MAC address in interface configuration mode or VLAN configuration mode.

SUMMARY STEPS

1. switch# configure terminal

2. switch(config-)# mac-address-table static mac_address vlan vlan-id < drop | interface < type slot / port >| port-channel number > [ auto-learn ]

3. (Optional) switch(config-)# no mac-address-table static mac_address vlan vlan-id

DETAILED STEPS

Command or Action	Purpose
Step 1	switch# configure terminal	Enters configuration mode.
Step 2	switch(config-)# mac-address-table static mac_address vlan vlan-id < drop | interface < type slot / port >| port-channel number > [ auto-learn ]	Specifies a static address to add to the MAC address table. If you enable the auto-learn option, the switch will update the entry if the same MAC address is seen on a different port.
Step 3	switch(config-)# no mac-address-table static mac_address vlan vlan-id	(Optional) Deletes the static entry from the MAC address table.

This example shows how to put a static entry in the MAC address table:

switch# configure terminal 

switch(config)# mac-address-table static 12ab.47dd.ff89 vlan 3 interface ethernet 2/1 

You can use the mac-address-table static command to assign a static MAC address to a virtual interface.

Configuring the Aging Time for the MAC Table

You can configure the amount of time that an entry (the packet source MAC address and port that packet ingresses) remain in the MAC table.

Note	You can also configure MAC aging time in interface configuration mode or VLAN configuration mode.

SUMMARY STEPS

1. switch# configure terminal

2. switch(config)# mac-address-table aging-time seconds [ vlan vlan_id ]

DETAILED STEPS

Command or Action	Purpose
Step 1	switch# configure terminal	Enters configuration mode.
Step 2	switch(config)# mac-address-table aging-time seconds [ vlan vlan_id ]	Specifies the time before an entry ages out and is discarded from the MAC address table. The range is from 0 to 1000000; the default is 300 seconds. Entering the value 0 disables the MAC aging. If a VLAN is not specified, the aging specification applies to all VLANs.

This example shows how to set the aging time for entries in the MAC address table to 600 seconds (10 minutes):

switch# configure terminal 

switch(config)# mac-address-table aging-time 600 

Clearing Dynamic Addresses from the MAC Table

You can clear all dynamic entries in the MAC address table.

Command	Purpose
switch(config)# clear mac-address-table dynamic < address mac-addr > < interface [ type slot / port | port-channel number >	Clears the dynamic address entries from the MAC address table.

This example shows how to clear the dynamic entries in the MAC address table:

switch# clear mac-address-table dynamic 

Verifying the MAC Address Configuration

To display MAC address configuration information, perform one of these tasks:

Command	Purpose
switch# show mac-address-table aging-time	Displays the MAC address aging time for all VLANs defined in the switch.
switch# show mac-address-table	Displays the contents of the MAC address table.

This example shows how to display the MAC address table:

switch# show mac-address-table 

VLAN MAC Address Type Age Port

1 0018.b967.3cd0 dynamic 10 Eth1/3

1 001c.b05a.5380 dynamic 200 Eth1/3

This example shows how to display the current aging time:

switch# show mac-address-table aging-time 

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Mac адрес роутера cisco

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Свежие записи

MAC-адрес — физический адрес любого устройство в сети (компьютера или сервера). Бывают ситуации, когда инженеры не имеют возможности «вживую» проверить оборудование, но при этом требуется знать, какое устройство подключено к порту коммутатора. В этом случае они используют удаленный доступ и смотрят таблицу MAC-адресов, которая есть на любом коммутаторе Cisco.

Смотрим MAC-адреса на порту коммутатора

Рассмотрим простейший случай. В нашей сети имеется один коммутатор, к которому подключены два компьютера и один сервер.

Мы не знаем, какое устройство подключено к какому порту. Но имеем удаленный доступ к свичу и всем хостам. Для того, чтобы вывести таблицу MAC-адресов в Cisco используется команда:

Посмотрим вывод команды на sw1:

Таблица содержим четыре столбца. Для нас важно, что она показывает MAC-адрес и соответствующий ему порт. Теперь, например, мы хотим узнать к какому порту подключен наш сервер. Для этого, узнаем MAC-адрес сервера, удаленно подключившись к нему. Вводим команду

Видим MAC 0003.E464.56A1 — соответствует порту fast Ethernet 0/10. Таким образом, становится понятно к какому порту коммутатора Cisco подключен сервер.

Важно! Всегда подписывайте назначения портов. Это можно сделать с помощью команды description.

Смотрим MAC-адреса в определенном VLAN’e

В этом случае разделим сеть компьютеров и сервера на два VLAN:

• для компьютеров PC-1 и PC-2 создадим VLAN 10 и сеть 192.168.10.0/24
• для сервера создадим VLAN 20 и сеть 192.168.20.0/24

Чтобы посмотреть какие устройства находятся в 10 vlan’e на sw1 вводим команду

# show mac-address-table vlan 10

При этом будет также отображаться таблица с MAC-адресами и соответствующими им портами.

Определяем MAC-адрес по IP-адресу

Но что, если нам нужно по IP-адресу определить MAC-адрес устройства. В этом случае нам поможет протокол ARP.

ARP — сетевой протокол, позволяющий по известному IP-адресу компьютера, получить его MAC-адрес. Если компьютер A в сети Ethernet не знает физический адреса компьютера B — он отправляет широковещательный ARP-запрос. Компьютер B отправляет ARP-ответ, в котором и содержится его MAC. После чего компьютер A записывает соответствие IP и MAC к себе в ARP-таблицу.

Роутер также содержит в себе ARP-таблицу. Чтобы посмотреть ее на R1 вводим команду:

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