Category Archives: Uncategorized


OTV Header Format Some consideration must be given to the MTU across the transport infrastructure. Consider the OTV packet header layout. A 42 byte OTV header is added and the DF (Don’t Fragment) bit is set on ALL OTV packets. The DF bit is set because the Nexus 7000 does not support fragmentation and reassembly. …

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vPC Role

There are two defined vPC roles: primary and secondary.vPC role defines which of the two vPC peer devices processes Bridge Protocol Data Units (BPDUs) and responds to Address Resolution Protocol (ARP).Use role priority <value> command (under vPC domain configuration context) to force vPC role to primary for a dedicated peer device.<value> ranges from 1 to …

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Identify iSCSI traffic : class-map type qos class-iscsimatch protocol iscsimatch cos 4class-map type queuing class-iscsimatch qos-group 4policy-map type qos iscsi-in-policyclass type qos class-fcoeset qos-group 1class type qos class-iscsiset qos-group 4 policy-map type queuing iscsi-in-policyclass type queuing class-iscsibandwidth percent 10class type queuing class-fcoebandwidth percent 10class type queuing class-defaultbandwidth percent 80policy-map type queuing iscsi-out-policyclass type queuing class-iscsibandwidth …

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iSCSI Ports

iSCSI uses TCP (typically TCP ports 860 and 3260).


The Cisco Nexus 5000 Series switch is a Layer 2 device. This means it does not fragment frames. As a result, the switch cannot have two ports in the same Layer 2 domain with different maximum transmission units (MTUs). A per-physical Ethernet interface MTU is not supported. Instead, the MTU is set according to the QoS classes. You modify …

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MTU over vPC N7K.

Jumbo frames are enabled by default on the vPC peer link. No MTU size configured, just system jumbomtu 9216 (Which is default) N7K-N7K-DC1-3(config-if)# ping pack 9000 PING ( 9000 data bytes 9008 bytes from icmp_seq=0 ttl=254 time=8.365 ms Request 1 timed out 9008 bytes from icmp_seq=2 ttl=254 time=8.141 ms Request 3 …

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Do not enter the no cfs eth distribute or the no cfs distribute command. You must enable CFSoE for vPC functionality. If you do enter either of these commands with vPC enabled, the system displays an error message. When you enter the show cfs application command, the output displays “Physical-eth,” which shows the applications that are using CFSoE

vNIC creation UCS for ESXi

It is critical that the “Enable Failover” checkbox SHOULD NOT be selected. There will be no “Native VLAN” selected since the installation of ESXi will have a vlan tag for the service console.

OSPF Type 1 vs Type 2

A type 1 route has a metric that is the sum of the internal OSPF cost and the external redistributed cost. A type 2 route has a metric equal only to the redistributed cost.


feature vrrp int vlan 30 vrrp 1 address prioirty 200 (Higher is better) no shut N7K-N7K-DC1-2(config-if-vrrp)# sh vrrp Interface VR IpVersion Pri Time Pre State VR IP addr ————————————————————— Vlan30 1 IPV4 100 1 s Y Master N7K-N7K-DC1-2(config-if-vrrp)# sh vrrp det Vlan30 – Group 1 (IPV4) State is Master Virtual IP address is …

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