Reservation on Layer2 without STP
The STP protocol was invented by the standards of information technology in the Stone Age. In those days, the task of backup and security was already in place, with a sufficiently long convergence time, STP protected the network from broadcast storms on the one hand (when looping) and provided a certain level of redundancy on the other. With the increase in the effect of Dig Data and the maximum use of both computing and bandwidth, STP began to grow into various "lotions" and grew to MSTP, which was designed to load all available links between the equipment as much as possible by building a tree for vlan groups. But what if there is a lot of traffic in vlan and the bandwidth of one physical line is not enough?
This article will discuss an example of practical implementation of a protocol of the form Multi-Chassis Link Aggregation Group (MC LAG) on HP ProCurve equipment.
Distributed Trunking (DT) - HP’s communication channel aggregation technology that allows 2 pieces of equipment to be used at one end of the aggregation, supported by 5400, 3500, 8200 series switches.
Next, we’ll analyze the circuit and the use of DT technology in it, as well as options for connecting various technologies to this technology equipment. The example did not call for solving specific problems, but I think the ideas used in this scheme will help to assess the advantages and disadvantages of the approach to building L2 networks.
General cable connection scheme. Parts of which we will consider the
scheme for connecting access level switches to kernel switches
The use of the STP family protocol in this scheme is not optimal. At high load, in any of the vlan's, the maximum speed will be limited by the speed of the channel to the kernel switch, in the particular case of 1 Gb / s. If the volume of traffic is not constant, it is quite difficult to determine the groups for MSTP, getting at least some balance in the lines. We introduce DT technology for kernel switches. Switches ESC1 and ESC2 are combined into one logical switch, on access switches aggregate the lines to the kernel switch. As a result, the logical circuit L2 will have the following form.
Thus, the circuit does not suffer from looping and provides a bandwidth of 2 Gbit / s towards the core.
A little more about the configuration and functions of the ports.
Inter-Switch Connection (ISC) is responsible for transferring data between the group switches; there can be either a separate port or a group of aggregated lines.
Peer-keepalive is responsible for monitoring the life of a partner, only service information and Hello packets are transmitted, traffic does not go.
The Distributed Trunk Interface (DTI) is part of the shared logical line of the virtual switch.
Due to the limited set of equipment on which this technology can be implemented, I will not describe its configuration, and there are enough resources with sufficiently detailed manuals, thousand .
For devices on a network connected to DTI ports, a pair of switches is visible as one, this aspect allows you to connect any equipment capable of aggregation.
I’ll give a few examples, with switches it’s easiest, they almost all know how to aggregate up-links, we just combine a couple of ports directed to the kernel and that’s it. With routers, things are a little more complicated, not all of them can use LAG (Link Aggregatin Group). In particular, for Cisco equipment, the 3925 router can EtherCnannel, and 1841 can not (without an additional switch module). On 3925 we combine two ports on EtherCnannel and all. But since 1841 you have to be smart, in practice, to solve the problem, a bunch of BeckUp interface + ip unnambered technologies was used. I suspect that it was possible to use the BackUp Interface + bridg group in a bunch, but in practice it has not been verified. Perhaps the habbschestvo will offer other options.
With servers, everything is still quite simple, for Windows servers and server network cards, most often there are drivers or utilities that allow combining network interfaces, for VMware there is NIC Teaming, etc.
In conclusion, I would like to say that this approach to building L2 networks has already been developed in the technology of large players, there are VSS and VPC from Cisco, DT and IRF from HP. Everything is moving towards the maximum use of all capacities of the equipment park with a sufficient level of redundancy, and technologies that do not meet these requirements are leaving.
This article will discuss an example of practical implementation of a protocol of the form Multi-Chassis Link Aggregation Group (MC LAG) on HP ProCurve equipment.
Distributed Trunking (DT) - HP’s communication channel aggregation technology that allows 2 pieces of equipment to be used at one end of the aggregation, supported by 5400, 3500, 8200 series switches.
Next, we’ll analyze the circuit and the use of DT technology in it, as well as options for connecting various technologies to this technology equipment. The example did not call for solving specific problems, but I think the ideas used in this scheme will help to assess the advantages and disadvantages of the approach to building L2 networks.
General cable connection scheme. Parts of which we will consider the
scheme for connecting access level switches to kernel switches
The use of the STP family protocol in this scheme is not optimal. At high load, in any of the vlan's, the maximum speed will be limited by the speed of the channel to the kernel switch, in the particular case of 1 Gb / s. If the volume of traffic is not constant, it is quite difficult to determine the groups for MSTP, getting at least some balance in the lines. We introduce DT technology for kernel switches. Switches ESC1 and ESC2 are combined into one logical switch, on access switches aggregate the lines to the kernel switch. As a result, the logical circuit L2 will have the following form.
Thus, the circuit does not suffer from looping and provides a bandwidth of 2 Gbit / s towards the core.
A little more about the configuration and functions of the ports.
Inter-Switch Connection (ISC) is responsible for transferring data between the group switches; there can be either a separate port or a group of aggregated lines.
Peer-keepalive is responsible for monitoring the life of a partner, only service information and Hello packets are transmitted, traffic does not go.
The Distributed Trunk Interface (DTI) is part of the shared logical line of the virtual switch.
Due to the limited set of equipment on which this technology can be implemented, I will not describe its configuration, and there are enough resources with sufficiently detailed manuals, thousand .
For devices on a network connected to DTI ports, a pair of switches is visible as one, this aspect allows you to connect any equipment capable of aggregation.
I’ll give a few examples, with switches it’s easiest, they almost all know how to aggregate up-links, we just combine a couple of ports directed to the kernel and that’s it. With routers, things are a little more complicated, not all of them can use LAG (Link Aggregatin Group). In particular, for Cisco equipment, the 3925 router can EtherCnannel, and 1841 can not (without an additional switch module). On 3925 we combine two ports on EtherCnannel and all. But since 1841 you have to be smart, in practice, to solve the problem, a bunch of BeckUp interface + ip unnambered technologies was used. I suspect that it was possible to use the BackUp Interface + bridg group in a bunch, but in practice it has not been verified. Perhaps the habbschestvo will offer other options.
With servers, everything is still quite simple, for Windows servers and server network cards, most often there are drivers or utilities that allow combining network interfaces, for VMware there is NIC Teaming, etc.
In conclusion, I would like to say that this approach to building L2 networks has already been developed in the technology of large players, there are VSS and VPC from Cisco, DT and IRF from HP. Everything is moving towards the maximum use of all capacities of the equipment park with a sufficient level of redundancy, and technologies that do not meet these requirements are leaving.