Introduction
This article is part of a series on deploying BIG-IPs with bypass switches and network packet brokers. These devices allow for the transparent integration of network security tools with little to no network redesign and configuration change. For more information about bypass switch devices refer to https://en.wikipedia.org/wiki/Bypass_switch; for network packet brokers, refer to https://www.ixiacom.com/company/blog/network-packet-brokers-abcs-network-visibility and https://www.gigamon.com/campaigns/next-generation-network-packet-broker.html. The article series introduces network designs to forward traffic to the inline tools at layer 2 (L2).
This article covers the design and implementation of the Gigamon Bypass Switch / Network Packet Broker in conjunction with the BIG-IP i5800 appliance and Virtual Wire (vWire) with LACP Mode. This article covers LACP Mode deployment mentioned in article https://devcentral.f5.com/s/articles/L2-Deployment-of-BIG-IP-with-Gigamon.
Network Topology
Below diagram is a representation of the actual lab network. This shows deployment of BIG-IP with Gigamon.
Figure 1 - Topology with MLAG and LAG before deployment of Gigamon and BIG-IP
Figure 2 - Topology with MLAG and LAG after deployment of Gigamon and BIG-IP
Figure 3 - Connection between Gigamon and BIG-IP
Hardware Specification
Hardware used in this article are
- BIG-IP i5800
- GigaVUE-HC1
- Arista DCS-7010T-48 (all the four switches)
Note: All the Interfaces/Ports are 1G speed
Software Specification
Software used in this article are
- BIG-IP 16.1.0
- GigaVUE-OS 5.7.01
- Arista 4.21.3F (North Switches)
- Arista 4.19.2F (South Switches)
Switch Configuration
Switch Configuration is same as previous article https://devcentral.f5.com/s/articles/BIG-IP-L2-V-Wire-LACP-Passthorugh-Deployment-with-Gigamon
Note: In above mentioned configuration switch ports are configured as access port to allow vlan 120, so BIG-IP will receive untagged frames. In case to have tagged frame, configure switch ports as trunk ports. In this article, below scenarios are tested with Tagged frames.
Gigamon Configuration
Gigamon Configuration is same as previous article https://devcentral.f5.com/s/articles/BIG-IP-L2-vWire-LACP-Passthrough-Deployment-with-1-to-1-mapping...
BIG-IP Configuration
BIG-IP configuration is exactly same as configuration mentioned in https://devcentral.f5.com/s/articles/L2-Deployment-of-BIG-IP-with-Gigamon
This article is specific to LACP Mode, find below trunk configuration with LACP mode enabled.
Figure 4 - Trunk configuration with LACP enabled
Note: For LACP mode, in vWire configuration Propagate Virtual Wire Link Status should be disabled.
Scenarios
As per Figure 2 and 3, setup is completely up and functional. As LACP passthrough mode configured in BIG-IP, LACP frames will passthrough BIG-IP. LACP will be established between North and South Switches. ICMP traffic is used to represent network traffic from the north switches to the south switches.
Scenario 1: Traffic flow through BIG-IP with North and South Switches configured in LACP active mode
Above configurations shows that all the four switches are configured with LACP active mode.
Figure 5 - MLAG and LAG status after deployment of BIG-IP and Gigamon with Switches configured in LACP AC TIVE mode
Figure 5 shows that port-channels 120 and 121 are active at both North Switches and South Switches. Above configuration shows MLAG configured at North Switches and LAG configured at South Switches.
Figure 6 - ICMP traffic flow from client to server through BIG-IP 
Figure 7 - Actor ID of BIG-IP
Figure 8 - LACP neighbor details in switches
Figure 7 and Figure 8 shows LACP is established between Switches and BIG-IP.
Scenario 2: Traffic flow through BIG-IP with North and South Switches configured in LACP Passive mode
North Switch 1:
interface Ethernet36 channel-group 120 mode passive interface Ethernet37 channel-group 121 mode passive
North Switch 2:
interface Ethernet37 channel-group 120 mode passive interface Ethernet36 channel-group 121 mode passive
South Switch 1:
interface Ethernet36 channel-group 120 mode passive interface Ethernet37 channel-group 120 mode passive
South Switch 2:
interface Ethernet36 channel-group 121 mode passive interface Ethernet37 channel-group 121 mode passive
Figure 9 - MLAG and LAG status after deployment of BIG-IP and Gigamon with Switches configured in LACP Passive mode
Figure 9 shows that port-channels 120 and 121 are active at both North Switches and South Switches. Above configuration shows MLAG configured at North Switches and LAG configured at South Switches.
Figure 10 - ICMP traffic flow from client to server through BIG-IP
Scenario 3: Active BIG-IP link goes down in BIG-IP
Figure 10 shows that interface 1.1 of BIG-IP is active incoming interface and interface 1.2 of BIG-IP is active outgoing interface. Disabling BIG-IP interface 1.1 will make active link down as below
Figure 11 - BIG-IP interface 1.1 disabled
Figure 12 - Trunk state after BIG-IP interface 1.1 disabled
Figure 13 - MLAG and LAG status with interface 1.1 down
Figure 13 shows that port-channels 120 and 121 are active at both North Switches and South Switches. This shows that switches are not aware of link failure and it is been handled by Gigamon configuration.
Figure 14 - One of Inline Tool goes down after link failure
Figure 14 shows Inline Tool which is connected to interface 1.1 of BIG-IP goes down.
Figure 15 - Bypass enabled for specific flow
Figure 15 shows tool failure introduced bypass for Inline-network pair Bypass1 ( Interface 1.1 and 1.2)
If traffic hits interface 1.1 then Gigamon will send traffic directly to interface 1.2. This shows traffic bypassed BIG-IP.
Figure 16 - ICMP traffic flow from client to server bypassing BIG-IP
Figure 17 - Port Statistics of Gigamon
Figure 17 shows traffic reaches interface 1.1 of Gigamon and forwards to interface 1.2. Traffic is not routed to tool, as specific Inline-Network enabled with bypass.
In the same scenario, if traffic hits any other interface apart from interface 1.1 of Gigamon then traffic will be route to BIG-IP. Please note that only one Inline-network pair enables bypass, remaining 3 Inline-network pairs are still in normal forwarding state.
Scenario 4: BIG-IP goes down and bypass enabled in Gigamon
Figure 18 - All the BIG-IP interfaces disabled
Figure 19 - Inline tool status after BIG-IP goes down
Figure 19 shows that all the Inline Tool pair goes down once BIG-IP is down.
Figure 20 - Bypass enabled in Gigamon
Figure 20 shows bypass enabled in Gigamon and ensures there is no network failure. ICMP traffic still flows between ubuntu client and ubuntu server as below
Figure 21 - ICMP traffic flow from client to server bypassing BIG-IP
Conclusion
This article covers BIG-IP L2 Virtual Wire LACP mode deployment with Gigamon. Gigamon configured with one to one mapping between Inline-network and Inline-tool. No Inline-network group and Inline-tool group configured in Gigamon.
Observations of this deployment are as below
- As one to one mapping configured between Inline-network and Inline-tool, no additional tag inserted by Gigamon.
- As there is no additional tag in frames when reaching BIG-IP, this configuration works for both Tagged and Untagged packets.
- If any of the Inline Tool link goes down, Gigamon handles bypass. Switches will be still unware of the changes.
- If any of the Inline Tool Pairs goes down, then specific Inline-network enables bypass.
- If traffic hits bypass enabled Inline-network, then traffic will be bypassing BIG IP.
- If traffic hits Normal forward state Inline-Network, the traffic will be forwarded to BIG-IP.
- If BIG-IP goes down, Gigamon enables bypass and ensures there is no packet drop.
- Propagate Virtual Wire Link State should be disabled for LACP Mode in Virtual Wire Configuration