This article is the process of learning and self Ethernet switches forward frames of notes
A. Ethernet switches forward frames and self-learning process
- Currently, there are some features network switches include Layer on the market, called the three switches
- Ethernet Automatic exchange table frame gradually established through self-learning algorithm
Then look at the self-learning process and forwarding Ethernet frames
And three each switch connected to the host, the MAC address represented by capital letters
Appeal process is called self-learning switch.
Host not found in the B frame switching table,
Removing itself forwards the frame to all the interfaces ; start only this way, because there is not enough knowledge to forward frames; blindly forwarded only
The frame of the destination MAC address B, the host determines its own MAC judgment.
A frame address can be found in the switching table; then forwarding the frame according to the interface A of the destination address the address.
A clearly know the MAC address of. This time, do not blindly forwarded
Frame to host E relaxation process A
Effective Duration
II. Ethernet Switch Spanning Tree Protocol (STP)
When the two lines are faulty, you can not communicate, can only turn into three smaller network
Network loop will bring some problems, such as broadcast storms ;
the broadcast frame repeatedly forwarded between each switch.
In order to be redundant links to increase while improving network reliability; avoiding the problems caused by network loops, Ethernet switch using Spanning Tree Protocol (STP)
III. Virtual LAN (VLAN)
In the broadcast network should be avoided:
How can a large broadcast domains into smaller broadcast domains it? Use routers can broadcast domain
The router in network architecture in the third layer (network layer): Since the default router does not broadcast packets case of forwarding, router so it is natural to be broadcast domain
In this case, the virtual local area network technology emerges
Same VLAN internal broadcast communication can be realized; different internal VLAN broadcast communication can not be achieved
IV. Virtual LAN (VLAN) implementation
Virtual LAN (VLAN) technology is implemented on the switch. Switchboard was required to achieve two functions: one is able to handle frames with VLAN tags, i.e. IEEE 802.1Q frame; each of the other ports of the switch ports can support different types, the different types of interface port handling of frames All the different
following PVID to be described, each switch port and only one PVID
Our applications host A and is classified to VLAN2 B; C and D under the host to VLAN3; broadcast frame such VLAN2 VLAN3 is not transferred to go;
Host applications is classified as A, B, E, F to VLAN1, host C, D, G, H classified to VLAN2; because the default configuration port when first power switch belonging to VLAN1, the corresponding value of 1 PVID and the type of port is Access; therefore we need to switch to the corresponding configuration to meet the application requirements.
When interconnected by a plurality of VLAN switches together in Switched Ethernet, a switch connected to the host port should be set as Access, interconnection between the switch ports should be a Trunk
unique router port hybird Huawei
Ordinary Ethernet MAC frames transmitted from host B to A, the host A is received 802.1Q frame, unrecognized discarded.
Summarized as follows:
