Category: Configuration

Cisco 6500 VSS Configuration

It’s an old draft from 2010. Recently I was designing a network which VSS was on the topics, so it reminded me of the draft.

The Cisco Catalyst 6500 Series Virtual Switching System (VSS) allows the clustering of two chassis together into a single, logical entity. This technology allows for enhancements in all areas of network design, including high availability, scalability, management, and maintenance.

The Virtual Switching System is created by converting two standalone Catalyst 6500 systems to a Virtual Switching System. The conversion is a one-time process that requires a few simple configuration steps and a system reload. Once the individual chassis reload, they are converted into the Virtual Switching System.

All control plane functions are centrally managed by the active supervisor engine of the active virtual switch chassis, including:

  • Management(Simple Network Management Protocol [SNMP], Telnet, Secure Shell [SSH] Protocol, etc.)
  • Layer 2 Protocols (bridge protocol data units [BPDUs], protocol data units [PDUs], Link Aggregation Control
    Protocol [LACP], etc.)
  • Layer 3Protocols (routing protocols, etc.)
  • Software data path

The requirements to convert the 6500 into a Virtual Switching System are:

  • The VSS requires Supervisor Engine 720 with 10-GigabitEthernet ports. You must use either two VS-S720-10G-3C or two VS-S720-10G-3CXL supervisor engine modules.
  • The VSS requires 67xx seriesswitching modules.
  • The VSLEtherChannel supports only 10-Gigabit Ethernet ports.

Continue reading “Cisco 6500 VSS Configuration”

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OSPFv2 in NX-OS

When you configure a summary address, Cisco NX-OS automatically configures a discard route for the summary address to prevent routing black holes and route loops.

OSPFv2 has the following configuration guidelines and limitations:

  • You can have up to four instances of OSPFv2 in a VDC.
  • Cisco NX-OS displays areas in dotted decimal notation regardless of whether you enter the area in decimal or dotted decimal notation.
  • All OSPFv2 routers must operate in the same RFC compatibility mode. OSPFv2 for Cisco NX-OS complies with RFC 2328. Use the rfc1583compatibility command in router configuration mode if your network includes routers that support only RFC 1583.
  • You must configure RFC 1583 compatibility on any VRF that connects to routers running only RFC1583 compatible OSPF.
Reference bandwidth for link cost calculation 40 Gb/s
Product License Requirement
Cisco NX-OS OSPFv2 requires an Enterprise Services license. For a complete explanation of the Cisco NX-OS licensing scheme and how to obtain and apply licenses, see the Cisco NX-OS Licensing Guide. 
nexus7009(config)# feature ospf
Nexus7009(config-if)# ip router ospf 201 area 0.0.0.15

From http://www.cisco.com/en/US/docs/switches/datacenter/sw/5_x/nx-os/unicast/configuration/guide/l3_ospf.html

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IPX Vol.1 Switching Notes

Downstream switches inherit timers from the root (of each VLAN)

  • BPDUgurad blocks incoming BPDUs.
  • BPDUfilter blocks outgoing BPDUs.
  • bpdufilter default and bpduguard default work in conjunction with portfast default.
  • spanning-tree guard loop  is similar to UDLD, but users STP BPDU keepalive.
show spanning-tree mst [detail]
In MST, load-balancing with cost/port-priority is the same as CST, PVST.
interface f0/0
spanning-tree mst 1 cost 1
spanning-tree mst 2 port-p 0

All switches in the L2 transit path should know about the RSPAN remote-vlan, and the interconnections should be trunk. Remember to remove pruning for RSPAN VLAN from trunks.

IPphone tags voice traffic with CoS 5.

switchport voice vlan dot1p instructs the IP-phone to apply VLAN0 and CoS 5, so both Voice & Data share the same VLAN.

switchport voice vlan  automatically applies portfast.

mls qos trust device cisco–ipphone means only trust CoS if received from IP-phone which is detected by CDP.

Fallback Bridging is the concept of bridging non-routed protocols between SVIs or native L3 router interfaces on switches. Similar to CBR and IRB on routers.

bridge 1 protocol vlan-bridge
interface f0/1
 bridge 1
  • PVLAN requires Transparent VTP mode.
  • Whenever a task asks us to optimize a switch for memory or routing, it means “sdm prefer routing“
  • Macros do not accept “interface range”!
  • When filtering traffic using mac-access-list remember to allow Spanning-tree and ARP stuff!

HSRP

  • standby use-bia  : not using the vMAC
  • standby version 2  : Uses 224.0.0.102 for inter-router communications instead of 224.0.0.2
standby 1 ip 150.100.220.1
standby 1 priority  : default is 100
standby 1  : not default
standby 1 track 1 decrement  // same as  standby 1 track Serial0/1/0 20

Remember to add static arp for hosts when filtering ARP in LAB exam. (show arp)

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Nested Policy-map

Policy-maps do indeed have the ability to be nested inside other policy maps. When we engage in this nesting behavior, we refer to the policy as a hierarchical policy. This is typically done to configure multiple treatments to QoS. For example – we might want to traffic-shape all traffic to 3 MB; and then inside that 3 MB shaped traffic, guarantee Web traffic at least 1 MB of bandwidth.

Remember, we use a service-policy (normally done with interfaces) to  assign the QoS policies that we define inside the policy-map.

With the nesting of policy maps, there are some restrictions that you should be aware of. For example:

  • The set command is not supported on the child policy
  • The priority command can be used in either the parent or the child policy, but not both
  • The fair-queue command cannot be used in the parent

Here is an example of nesting policy maps:

Verifying your policy-map, is very simple thanks to the following show commands:

show policy-map
show policy-map interface int_name
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Private VLAN

  • Members of an isolated VLAN can only communicate with the promiscuous ports mapped
  • Members of a community VLAN can communicate with members of the same community and the promiscuous ports.

A two-way community acts like a regular community but has the additional aspect of allowing access control lists to check traffic going to and from (two ways) the VLAN and provides enhanced security within a private VLAN.

To configure PVLAN, VTP should be in transparent mode.

  1. Create primary private-vlan
  2. Create isolated/community VLAN
  3. Associating isolated/community VLANs to primary
  4. Configure spanning-tree mode and associating ports to PVLANs
  5. Mapping PVLANs under the primary VLAN interface
  6. To verify: show interface [primary PVLAN] private-vlan mapping

IPExpert, Vol.1, 2.28

You must configure VTP to transparent mode before you can create a private VLAN.
Private VLANs are configured in the context of a single switch and cannot have members on other switches. Private VLANs also carry TLVs that are not known to all types of Cisco switches.

Configuration

SWITCH(config)# vlan primary_number
SWITCH(vlan-config)# private-vlan primary
SWITCH(config)# vlan secondary_number
SWITCH(vlan-config)# private-vlan [isolated | community]
SWITCH(config)# vlan primary_number
SWITCH(vlan-config)# private-vlan association secondary_number_list [add secondary_number_list]
SWITCH(config)# interface type mod/port
SWITCH(config-if)# switchport
SWITCH(config-if)# switchport mode private-vlan host
SWITCH(config-if)# switchport mode private-vlan host-association primary_number secondary_number
SWITCH(config)# interface type mod/port
SWITCH(config-if)# switchport
SWITCH(config-if)# switchport mode private-vlan promiscuous
SWITCH(config-if)# switchport mode private-vlan mapping primary_number secondary_number
SWITCH(config)# interface primary_number
SWITCH(config-if)# ip address address mask
SWITCH(config-if)# private-vlan mapping primary_number secondary_number
show vlan private-vlan type
show interface private-vlan mapping
show interface type mod/port switchport
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