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2019 IT Blog Awards by Cisco

Today I’ve received a badge from Cisco. I made the finalist for the IT Blog Awards 2019 by Cisco in the Best Newcomer category! Discover all the awesome podcasts and resources. There are a lot of great blogs out there. To vote click here. Best Analysis – Does this blog provide insightful discussions? Houman Asefi How Does Internet Work mrnCCIEW Network Defense...

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Cisco NX-OS: VXLAN Asymmetric Routing

EVPN Integrated Routing and Bridging (IRB) has two options: Asymmetric IRB Symmetric IRB Assymetric IRB Ingress VTEP does both L2 and L3 lookup Egress VTEP does L2 lookup only => Bridge – Route – Bridge Pros: “easy” to configure – just copy/paste. Identical config with the only difference in SVI IP addresses. Cons: on the way back, traffic will be reversed...

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Cisco NX-OS: VXLAN BGP EVPN control plane

Two control planes for the VXLAN technology: Multicast control plane (flood-and learn) MP-BGP EVPN control plane MP-BGP EVPN is a standard-based VXLAN control protocol, that provides remote VTEP discovery and MAC/ARP learning. Ethernet Virtual Private Network (EVPN) reduces flooding in the network and resolves scalability concerns. MP-BGP is used to exchange information between VTEPs Devices might be MP-iBGP EVPN peers or...

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Cisco NX-OS: VXLAN Multicast Control Plane

Two control planes for the VXLAN technology: Multicast control plane (flood and learn) MP-BGP EVPN control plane Virtual Extensible Local Area Networks (VXLANs) allows to extend reachability of a VLAN within a data center over Layer 3. Every VTEP with specific VXLAN and certain VNI will join the same multicast group. To learn remote MAC addresses, the VTEP will use conversational...

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Cisco NS-OS: Virtual eXtensible LAN (VXLAN) Overview

VXLAN is a tunneling protocol that encapsulates Layer 2 Ethernet frames in Layer 3 UDP packets. Why VXLAN: VLAN Scalability  – expands VLAN name space VLANs use 12 bit -4096 values VXLAN uses 24 bit – 16777216 values allows layer 2 multipathing no STP uses layer 3 ECMP over CLOS fabric (like FabricPath) allows for multi-tenancy separate of customer traffic over shared...

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Cisco UC: ISR box-to-box REDundancy

The Interchassis High Availability feature (box-to-box redundancy) enables the configuration of pairs of routers to act as backup for each other. Failover: the standby router seamlessly takes over and starts processing call signaling and performing media forwarding tasks. Note: failover causes reboot by design. Configuration on ISR 4000 series Enable CUBE and redundancy on both routers: Configure an redundancy group with...

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Cisco UC: PRTG and SIP calls

I found several ways monitoring SIP calls in PRTG using SNMP. Monitor active calls using SIP legs/2 Monitor each dial-peer separately and combine them in the Sensor Factory Just monitor multiple OIDs in one Sensor Enable SNMP on the CUBE: 1. Monitor active calls using SIP legs Idea: check how many SIP legs on the voice gateways (show call active voice...

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Cisco NX-OS: FabricPath (FP)

FabricPath (FP) is a L2 Routing = “MAC-in-MAC” Routing. FabricPath is Cisco proprietary and works in the same way as TRILL (Transparent Interconnection of Lots of Links) that is an IETF standard. FP: to remove STP from the topology vPC: only 2 switches FP: full mesh, partial mesh, triangle, square etc Components: Classical Ethernet (CE) regular ethernet with regular flooding, regular...

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Cisco NX-OS: vPC & Failures

vPC Orphan Ports – Traffic from remote Orphan is allowed over Peer Link and exit via local Member– Traffic from remote Member is allowed over Peer Link and exit via local Orphan-Orphans ports should be avoided at all costs because PL is a bottleneck of the system Ideal: vPC Peers only have vPC Member Ports and all downstream devices are dual...

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Cisco NX-OS: vPC & FHRP

FHRP acts as active/active forwarding over vPC: traffic received in vPC Member Port of FHRP Standby to FHRP Virtual MAC is not forwarded over Peer Link to Active FHRP – essentially HSRP Standby acts as HSRP Active peer-gateway allows to proxy not only virtual active MAC address but also to proxy physical primary MAC address (in case destination MAC address is...