Common traffic aggregation scheme. Application area
Link Aggregation is used to combine several physical links to logical one to increase the overall throughput and reliability of the data transmission system.The total logical link bandwidth is a sum of all the participating physical links capabilities, and in case one of them failure, the system continues to operate using the remaining working links. There are tools to aggregate communication channels at the link (L2) and network (L3) levels, in this lesson we will review the aggregation at the link level.
The common aggregation scheme is shown in figure below. PC1 and PC2 are connected by two or more L2 links. Physically each one can be both wired and wireless.On each side, a device is allocated that establishes a logical connection with a similar functionality device on the opposite side. These devices are engaged in the data distribution between physical links, combined into logical one.
Figure 5.1 - Common traffic aggregation scheme
Combine device Ethernet interfaces using LAG
In InfiNet devices with Fast Ethernet ports, the maximum throughput of one port is limited by 100Base-TX standard. The radio module capacity, depending on the MCS and channel width, may be higher. For InfiLINK 2x2 LITE family and InfiMAN 2x2 CPE devices, the maximum achievable throughput reaches 180 Mbps bidirectional aggregated traffic. In case of connection via only one 100Base-TX port, it will not be possible to utilize the radio link completely in one direction. However, by using Link Aggregation, it is possible to combine the device ports into one logical link, it will allow to load the band available through the radio link in one direction more optimally.
Figure 5.2 - Link aggregation scheme between the radio device and the switch in the point-to-point topology
This configuration is applicable not only in point-to-point topologies. For example, Link Aggregation can be used only on one side, to increase the capacity of the base station sector (see figure).
Figure 5.3 - Link aggregation scheme between the radio device and the switch in the point-to-multipoint topology
To configure Link Aggregation on InfiNet devices use following instruction:
Step 1: Go to "Basic Settings → Network Settings" section and click the "Create LAG" button
Figure 5.4 - Create LAG interface
Step 2: Add aggregated ports to the LAG interface (eth0 and eth1 in our example).
Figure 5.5 - Adding ports to the LAG
Step 3: Select LACP mode, in the "Standard" mode LACP operates in accordance with the IEEE 802.3ad standard. In the "Fast mode" additional add-ons are used to significantly speed up the LACP response to changing environmental conditions, optimize aggregation system, and obtain more accurate statistics.
Caution: "Fast mode" is a proprietary LACP extension. Compatibility of this mode is guaranteed only with devices with the MINT protocol support.
Step 3a: If necessary, the management IP address can be assigned to a LAG interface or SVI.
Caution: If the management IP address might be assigned to the LAG interface, set an IP address first, and then make the interface active.
Figure 5.6 - Assigning an IP address to a LAG interface
Step 4: Go to "Basic Settings → MAC Switch" section and click the "Create Switch Group" button. Add the rf5.0 and lag0 interfaces.
Figure 5.7 - Create a switch group
Using LAG on the InfiMUX
The maximum bandwidth of the entire radio link can be increased using two radio links aggregation. InfiMUX switches allow to aggregate radio links into a single channel, the capacity of each link will be estimated in real time. The dynamic traffic distribution is based on the current characteristics of each link. To perform this, devices must be joined into a single MINT area using PRF interfaces.
Figure 5.8 - Links aggregation with using InfiMUX
Setting up the links aggregation according to the scheme on the figure above is performed in the following steps:
Step 1: To join all devices into a single MINT area, create PRF interfaces on all devices. Go to the "Basic Settings → Network Settings" section and click the "Create PRF" button, and set the "0" value.
Figure 5.9 - Creating a PRF interface on radio devices
Step 2: Go to the "Basic Settings → Link Settings" section enable PRF interface, and join rf5.0 and prf0 interfaces in "Join" subsection.
Figure 5.10 - Configuration of PRF interfaces on radio devices
Step 3: Create two PRF interfaces on each of the InfiMUX switches. Go to the "Basic Settings → Network Settings" section and click the "Create PRF" button.
Figure 5.11 - Creating a PRF interface on InfiMUX
Step 4: Set parent interfaces for created PRF. Use eth interfaces to which radio devices are connected as parents.
Figure 5.12 - Configuration of PRF interfaces on InfiMUX
Step 5: Go to the "Basic Settings → Link Settings" section enable both PRF interface, and join prf1 and prf2 interfaces in "Join" subsection.
Figure 5.13 - Configuration of PRF interfaces on InfiMUX
Step 6: On the InfiMUX switches go to the "Basic Settings → Network Settings" section and click the "Create LAG" button.
Figure 5.14 - Creating LAG interface on InfiMUX
Step 7: Add aggregated ports to the LAG interface (eth1 and eth2 in this example).
Figure 5.15 Configuration of LAG interface on InfiMUX
Step 8: On the radio devices go to the "Basic Settings → MAC Switch" section and click the "Create Switch Group" button. Add eth0 and rf5.0 interfaces to the switch group. Enable the "Repeater" option to allow the radio equipment transmit all data arriving on the Ethernet interface to the radio and vice versa.
Caution: The switching group number for the data transmission on Master 2 and Slave 2 must differ from the group number on Master1 and Slave 1, or it might cause the loop.
Figure 5.16 - Switch group settings on radio devices
Step 9: On the InfiMUX'es go to the "Basic Settings → MAC Switch" section and click the "Create Switch Group" button. Add eth0 and lag0 interfaces to the switch group.
Figure 5.17 Switch group settings on InfiMUX
Using LAG on third-party equipment
The scheme of using LAG on other manufacturers network equipment matches with the common aggregation scheme (Figure 5.1).
In this case, all settings related to aggregation are performed on switches 1 and 2, and the radio equipment acts as an L2 communication channel. On radio equipment, it is necessary to configure switch groups only, as it is shown in Figure 5.16.