CDP and LLDP
SW# show VLAN status
connected / notconnect /
VLAN trunk or 1.
VLANs Fa0/13+Fa0/14, Fa0/16 an Fa 0/17 are TRUNKS.
From PC we try to reach different VLANs
C:\ Doc and settings\admin\> ping 192.168.0.1
C:\ Doc and settings\admin\> ping 192.168.0.4
Но мы не можем пинговать к 3-му и 5-му раутеру:
C:\ Doc and settings\admin\> ping 192.168.0.2
C:\ Doc and settings\admin\> ping 192.168.0.3
C:\ Doc and settings\admin\> ping 192.168.0.5
Если мы будем посылать пинг к коммутатору SW, то пакеты также не дойдут
C:\ Doc and settings\admin\> ping 192.168.0.7 - 100% loss (все потерялись!)
SW1# show ip int brief
Routers 2, 3 and 5 are in VLAN 101
R2# ping 192.168.0.3
R2# ping 192.168.0.5 и то, и другое безрезультатно, хотя
R2# show arp
маршрутизатор знает MAC-адреса 3--го и 5-го маршрутизатора.
Можно проверить, как они взаимодействуют друг с другом, посылая пинг
от одного маршрутизатора к другим.
Те, которые в другом VLAN, не ответят.
R2 fries to figure the address of router 1, but it cannot have the responce back in.
VLAN 101 R2 MAC, R3 MAC, R5 MAC
VLAN 100 R1 MAC and R4 MAC
SW1# show mac address table vlan 100
SW1# show mac address table vlan 101
Можно посмотреть IP адреса, можно также отследить по динамическим show mac address table dynamic vlan 101
какие в виртуальной сети существуют динамические подсети и устройства с какими MAC-адресами подключены.
Но запоминать все мак-адреса - никто не будет, и существует удобная система для этого:
CDP
The Cisco Discovery Protocol (CDP) is a proprietary Data Link Layer network protocol developed by Cisco Systems. It is used to share information about other directly connected Cisco equipment, such as the operating system version and IP address. CDP can also be used for On-Demand Routing, which is a method of including routing information in CDP announcements so that dynamic routing protocols do not need to be used in simple network.
Cisco devices send CDP announcements to the multicast destination address 01-00-0c-cc-cc-cc, out each connected network interface. These multicast packets may be received by Cisco switches and other networking devices that support CDP into their connected network interface. This multicast destination is also used in other Cisco protocols such as VTP. By default, CDP announcements are sent every 60 seconds on interfaces that support Subnetwork Access Protocol (SNAP) headers, including Ethernet, Frame Relay and Asynchronous Transfer Mode (ATM). Each Cisco device that supports CDP stores the information received from other devices in a table that can be viewed using the show cdp neighbors command.
SW#show cdp neighbors
It tells you what deviced are connected to local ports.
This protocol should be ON by default.
SW#show cdp neighbors details
This will show you ID, IP, platform, version, VTP
If you don't know what is the equipment, use show cdp neighbors
It will show the platform=Cisco model.
Он также покажет, router это или switch в Capability codes, R, S, I=IGMP.
To enable CDP SW#cdp run
if you don't want CDP run
SW# no cdp run (globally for the platform)
or for any interface
SW (config)#int f0/1
SW (config)#no cdp enable (for this interface)
There is an open protocol for this which is LLDP.
Нейтрально-вендоровый протокол, открытый!
The Link Layer Discovery Protocol (LLDP) is a vendor-neutral Link Layer protocol in the Internet Protocol Suite used by network devices for advertising their identity, capabilities, and neighbors on a IEEE 802 local area network, principally wired Ethernet.
The protocol is formally referred to by the IEEE as Station and Media Access Control Connectivity Discovery specified in standards document IEEE 802.1AB.
LLDP performs functions similar to several proprietary protocols, such as the Cisco Discovery Protocol, Extreme Discovery Protocol, Nortel Discovery Protocol (also known as SONMP), and Microsoft's Link Layer Topology Discovery (LLTD).
connected / notconnect /
VLAN trunk or 1.
VLANs Fa0/13+Fa0/14, Fa0/16 an Fa 0/17 are TRUNKS.
From PC we try to reach different VLANs
C:\ Doc and settings\admin\> ping 192.168.0.1
C:\ Doc and settings\admin\> ping 192.168.0.4
Но мы не можем пинговать к 3-му и 5-му раутеру:
C:\ Doc and settings\admin\> ping 192.168.0.2
C:\ Doc and settings\admin\> ping 192.168.0.3
C:\ Doc and settings\admin\> ping 192.168.0.5
Если мы будем посылать пинг к коммутатору SW, то пакеты также не дойдут
C:\ Doc and settings\admin\> ping 192.168.0.7 - 100% loss (все потерялись!)
SW1# show ip int brief
Routers 2, 3 and 5 are in VLAN 101
R2# ping 192.168.0.3
R2# ping 192.168.0.5 и то, и другое безрезультатно, хотя
R2# show arp
маршрутизатор знает MAC-адреса 3--го и 5-го маршрутизатора.
Можно проверить, как они взаимодействуют друг с другом, посылая пинг
от одного маршрутизатора к другим.
Те, которые в другом VLAN, не ответят.
R2 fries to figure the address of router 1, but it cannot have the responce back in.
VLAN 101 R2 MAC, R3 MAC, R5 MAC
VLAN 100 R1 MAC and R4 MAC
SW1# show mac address table vlan 100
SW1# show mac address table vlan 101
Можно посмотреть IP адреса, можно также отследить по динамическим show mac address table dynamic vlan 101
какие в виртуальной сети существуют динамические подсети и устройства с какими MAC-адресами подключены.
Но запоминать все мак-адреса - никто не будет, и существует удобная система для этого:
CDP
The Cisco Discovery Protocol (CDP) is a proprietary Data Link Layer network protocol developed by Cisco Systems. It is used to share information about other directly connected Cisco equipment, such as the operating system version and IP address. CDP can also be used for On-Demand Routing, which is a method of including routing information in CDP announcements so that dynamic routing protocols do not need to be used in simple network.
Cisco devices send CDP announcements to the multicast destination address 01-00-0c-cc-cc-cc, out each connected network interface. These multicast packets may be received by Cisco switches and other networking devices that support CDP into their connected network interface. This multicast destination is also used in other Cisco protocols such as VTP. By default, CDP announcements are sent every 60 seconds on interfaces that support Subnetwork Access Protocol (SNAP) headers, including Ethernet, Frame Relay and Asynchronous Transfer Mode (ATM). Each Cisco device that supports CDP stores the information received from other devices in a table that can be viewed using the show cdp neighbors command.
SW#show cdp neighbors
It tells you what deviced are connected to local ports.
This protocol should be ON by default.
SW#show cdp neighbors details
This will show you ID, IP, platform, version, VTP
If you don't know what is the equipment, use show cdp neighbors
It will show the platform=Cisco model.
Он также покажет, router это или switch в Capability codes, R, S, I=IGMP.
To enable CDP SW#cdp run
if you don't want CDP run
SW# no cdp run (globally for the platform)
or for any interface
SW (config)#int f0/1
SW (config)#no cdp enable (for this interface)
There is an open protocol for this which is LLDP.
Нейтрально-вендоровый протокол, открытый!
The Link Layer Discovery Protocol (LLDP) is a vendor-neutral Link Layer protocol in the Internet Protocol Suite used by network devices for advertising their identity, capabilities, and neighbors on a IEEE 802 local area network, principally wired Ethernet.
The protocol is formally referred to by the IEEE as Station and Media Access Control Connectivity Discovery specified in standards document IEEE 802.1AB.
LLDP performs functions similar to several proprietary protocols, such as the Cisco Discovery Protocol, Extreme Discovery Protocol, Nortel Discovery Protocol (also known as SONMP), and Microsoft's Link Layer Topology Discovery (LLTD).