Thinking about MPLS and VLAN isolation technology

?? In the network environment, in order to isolate and divide the network, avoid inter-network interference and broadcast storms, define a variety of forms of isolation. There are hardware-based isolation and network protocol isolation, as well as the isolation of subnet segments (subnet masks).
?? MPLS and VLAN isolation, based on the software protocol, there is a certain hardware technical support, with these two tags of the packet, before or after the device, the protocol itself to do add and remove the label processing, in order to distinguish different network data at the aggregation of packet processing.

1.MPLS (Multiprotocol Label Switching)

?? A label between two and three layers of exchange, commonly known as 2.5-layer switching (two-layer interchange –>mac address Exchange, three-layer interchange –>ip address Exchange)

2.Vlan (virtual local area network)

?? tags in the Ethernet frame structure, refer to the 802.10 standard

3. Switch-to-hub (hub) Isolation

?? From the OSI architecture, the hub belongs to the OSI first layer physical layer device, and the switch belongs to the OSI's second Layer data link layer device. Also means that the hub is only the transmission of data synchronization, amplification and shaping role, the data transmission of short frames, fragments, etc. can not be effectively processed, can not guarantee the integrity and correctness of data transmission, and the switch can not only be transmitted to the transmission of synchronization, amplification and shaping, and can filter short frames, fragments and so on.
?? From the point of view of work, the hub is a broadcast mode, that is, when one of the hubs of the hub works, all other ports can listen to information, prone to broadcast storms, network performance will be greatly affected when the network is large. The switch can avoid this phenomenon, when the switch after the operation, only the port and the destination port to make the request to each other and not affect the other ports, so the switch can isolate the conflict and disease effectively suppress the generation of broadcast storms.
?? From the bandwidth point of view, the hub regardless of how many ports, all the ports are a shared bandwidth, at the same time only two ports to transmit data other ports can only wait, while the hub only works in half-duplex mode, and for the switch, each port has an exclusive bandwidth, While two ports work without affecting the work of other ports, the switch can operate in half-duplex mode and work in full-duplex mode.

4. Autonomous systems as and routing protocols

?? The multi-Exit autonomous system (multihomed as), which has more than one autonomous system connected to other autonomous systems, AS2

?? End Autonomous System (stub as), autonomous systems connected to only one other autonomous system, AS1 and AS2

?? Relay Autonomous System
Relay autonomous system, an autonomous system to provide connectivity services for several isolated networks by itself, AS2

?? IGP Internal Gateway Protocol, internal to the same as autonomous system
?? EGP External Gateway protocol, between different as autonomous systems
?? BGP Border Gateway Protocol, BGP builds on the experience of EGP, ensuring that there are multiple connections between unrelated routing domains, that is, the isolation between routers

BGP message Data

?? BGP uses four message types such as:
?? Open message: The open message is the first message sent after the TCP connection is established to establish a connection relationship between the BGP peers.
?? KeepAlive message: BGP periodically sends a KEEPALIVE message to the peer to maintain the validity of the connection.
?? Update message: The update message is used to exchange routing information between peers. It can either publish the routing information or revoke the unreachable routing information.
?? Notification message: When BGP detects an error state, it issues a notification message to the peer, and then the BGP connection is immediately interrupted.

BGP Fabric Data? Three Tables of BGP

• Neighbor Tables Enumerate BGP neighbor information
• BGP forwarding lists the paths from each BGP secondary, there may be multiple paths, and each path has attributes
• IP routing table enumerates the best paths to reach the network

Thinking about MPLS and VLAN isolation technology