Network Virtualization Technology (i) Cisco VSS

VSS uses the inter-chassis nsf/sso as the primary high-availability mechanism between the two enclosures. One Virtual Switch member chassis will be a member of the primary virtual switch, and another member will be in the hot wait state of the control Panel. The data panels for both enclosures are available, so the total traffic forwarding capability is 1440Gbps. When a virtual switch member fails, there is no need for protocol re-convergence in the network. The access layer or core layer switches continue to forward traffic because they only detect a link failure in the EtherChannel bundle, so there is no need to re-converge any protocol. There is no interruption in traffic transmitted over VSS. In traditional mode, a switch failure can result in convergence of multiple control protocols, such as STP, HSRP, and routing protocols, and the VSS mechanism is far better than when a switch fails.

VSS Overview 　　 VSS (Virtual Switch System):Cisco's virtualization technology for virtualizing two physical Catalyst 6500 series switches into a single logical switch is called VSS (Virtual switching system).VSL (Virtual Switch Link): An out-of-band link with a Gigabit Ethernet connection between Virtual Switch members (using EtherChannel, up to 8) is called VSL. Control traffic and data traffic that carries two physical switches.

　　VSLP (Virtual Switch Link Protocol): The VSL protocol contains two sub-protocols, LMP and RRP.

　　LMP (Link Management Protocol): LMP is a protocol running on a VSL link that swaps state information between two enclosures and sends a heartbeat.

　　RRP (Role Resolution Protocol): The RRP protocol is also a protocol that runs on a VSL link to deal with the master/standby relationship between two enclosures.

　　MEC (multichassis EtherChannel): VSS cross-Physical chassis port aggregation, up to 512 EtherChannel, removal of the VSL connection requires a minimum of 2 EtherChannel, up to 510 support.

VSS System Management

　Management level is equivalent to a switch, the main engine is active state, the standby engine is the standby state, the console connection master engine can be used for management, the connection backup engine cannot manage the switch.

VSS System Redundancy

VSS uses SSO (Stateful switchover) and NSF (nonstop forwarding) for fast switching of engine and route forwarding. NSF is a three-tier device configured with two RP cards, if you run OSPF, EIGRP, BGP, ISIS, and other routing protocols, if you do not configure the nsf,a/p RP Switchover requires 5min, and the nsf,a/p RP switch is configured with only 5sec.

VSS Dual Live Detection

VSS uses the EPAGP (enhanced PAGP) protocol, IP BFD, Fast Hello Packets, and three ways to perform dual-live detection and forward recovery. In extreme cases, when two enclosures are dual-active, the primary switch will shutdown other ports than the VSL link port, and the original standby switch hosts the forwarding task. This avoids collisions in the network.

VSS Hardware and software requirements

VSS Benefits

1. Implementing port aggregation across chassis (MEC)
2. The single switch has a bandwidth capacity of 720Gbps and expands to 1.4Tbps through VSS virtual post-bandwidth capacity.
3. No two-tier loop networking can be implemented without the use of STP protocols.
4. There is no need to use HSRP, VRRP, GLBP protocol networking.
5. Cross-chassis port aggregation can improve link utilization and simplify network nodes.

VSS Configuration

1. Save current device configuration

2. Configuring SSO (Stateful Switchover) and NSF (Nonstop forwarding)

switch-1(config) # redundancy enters redundancy configswitch-1(config-red) # mode Ssoswitch-1(config-Red) # Exitswitch-1(config) # router OSPF -(for example, running the OSPF protocol) Switch-1(config-Router) # Nsfswitch-1(config-Router) # Endswitch-1# Switch-2(config) # redundancy enters redundancy configswitch-2(config-red) # mode Ssoswitch-2(config-Red) # Exitswitch-2(config) # router OSPF -(for example, running the OSPF protocol) Switch-2(config-Router) # Nsfswitch-2(config-Router) # Endswitch-2#

3. Configure Virtual Switch domain and switch number

switch-1Switch-11switch-1(config-vs-  Domain) # exit switch-2switch-22switch- 2 (config-vs-domain) # exit the switch number is not saved in the configuration file because the two switch profiles are the same, but the two switch numbers must not be the same. 

4. Configuring VSL Port Aggregation

switch-1(config) # interface Port-channelTenSwitch-1(config-if) # switch Virtual link1Switch-1(config-if) # no Shutdownswitch-1(config-if) # Exitswitch-1(config) # interface range Tengigabitethernet3/1Switch-1(config-if) # Channel-groupTenmode Onswitch-1(config-if) # no Shutdownswitch-1(config) # interface range Tengigabitethernet5/1Switch-1(config-if) # Channel-groupTenmode Onswitch-1(config-if) # no shutdown Switch-2(config) # interface Port-channel -Switch-2(config-if) # switch Virtual link2Switch-2(config-if) # no Shutdownswitch-2(config-if) # Exitswitch-2(config) # interface range Tengigabitethernet3/1Switch-2(config-if) # Channel-group -mode Onswitch-2(config-if) # no Shutdownswitch-2(config) # interface range Tengigabitethernet5/1Switch-2(config-if) # Channel-group -mode Onswitch-2(config-if# No shutdown requires a minimum of two VSL ports in order to ensure link redundancy, preferably on two boards. 

5. Convert the chassis to VSS mode

before converting to VSS ensure that all modules are working in PFC3C mode switch-1(config) # Platform hardware VSL PFC mode Pfc3cswitch-  2(config) # Platform hardware VSL PFC mode pfc3c can be viewed in PFC mode via show platform hardware PFC mode. Switch-1# switch Convert mode virtualswitch-2# switch Convert mode Virtual device restarts when VSS is converted and is VSS mode when boot is complete

6. Configure dual-Live detection (EPAGP mode)

Router (config) # interface Port-channel -Router (config-if) # shutdownrouter (config-if) # exitrouter (config) # switch virtual domain -Router (config-vs-domain) #dual-Active detection pagprouter (config-vs-domain) #dual-active Detection PAgP Trust Channel-group -Router (config-vs-domain) # exitrouter (config) # interface Port-channel -Router (config-if) # no Shutdownrouter (config-if# Exit before configuring EPAGP, you will first use the VSL port-channel shutdown, otherwise cannot be configured EPAGP

7. Check the VSS status

router# Show switch virtualswitch mode:virtual switchvirtual switch domain number: -Local Switch Number:1Local Switch Operational role:virtual switch activepeer switch number:2Peer Switch Operational role:virtual switch Standby router# show switch Virtual roleswitch switch Status Preempt Pri Ority Role Session IDNumber Oper (Conf) Oper (Conf) Local Remote------------------------------------------------------------------LOCAL1Up FALSE (N) -( -) ACTIVE0 0REMOTE2Up FALSE (N) -( -) STANDBY8158 1991In dual-Active recovery Mode:no router# show switch virtual LINKVSL STATUS:UPVSL Uptime:4Hours -minutesvsl SCP ping:pass okvsl ICC (Ping): Passvsl Control link:te1/5/1

Network Virtualization Technology (i) Cisco VSS