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Linux on Windows, Python IDE, and VirtualEnv

Linux on Windows For some tasks, it is still easier to use Windows (Cisco IP Communicator, UCCX Script Editor, CUCM RTMT, etc.), but there is an option to include Linux into the workflow. Recently I discovered the WLS: Windows Subsystem for Linux (WSL), which allows us to install and run sort of Linux on Windows10 side-by-side. Go to Microsoft Store and...

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Python: Script structure

I decided to make some Python notes. Since there is a ton of information about Python, these notes will be mostly for my reference but if they help anyone – it will be great. The best way to understand it – try it and make a note:) starting with the basic script structure: starting with the basic script structure: #!/usr/bin/env python:...

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Cisco UC: CUBE Enhancements

CUBE 10.0.0 [IOS 15.4(2)T / IOS-XE 3.12] introduces the concept of Destination Server Group, which supports multiple session targets (up to 5) to be defined in a group and applied to a single outbound dial-peer. This feature configures a server group (group of server addresses) that can be referenced from an outbound dial peer. This reduces the need to configure multiple...

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Cisco UC: SIP and TranslatorX

I can’t say how many times I had to configure SIP on Cisco voice gateways, troubleshoot SIP, enable SIP, etc. The second problem, after fear of loading and stuck the router using the “debug ccsip messages” command, is to filter and find the call in debugging turned on. If there is a way to collect all sip logs from the console...

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A little more Ansible

Templates There is a way to run playbook locally on the PC (generating some files, scripts or configs) using templates. Let’s say there is a template file (switch_template.j2): hostname {{ item.hostname }} ! interface loopback 0 ip address {{ item.loopback }} ! router eigrp 100 As a result of this playbook, 2 files will be generated: R1.txt and R2.txt Conditions Using...

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Ansible with Cisco

Documentation A good point to start – Ansible User Guide. Network modules (ios/nxos/ios-xr, aci, junos etc) – Module Index – Network Modules IOS/NXOS Command Modules IOS NXOS IOS There is are a way to run multiple commands Very useful for debugging to show output in the terminal: – name: show output     debug:          var: output Some...

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Ansible Intro

Automation is everywhere. I decided to take a quick look into Ansible Ansible is the simplest way to automate apps and IT infrastructure using SSH, with no agents to install on remote systems. Here is Intro to Ansible. Ansible – Open Source IT Automation Platform Notes: using SSH and does not require an agent written in Python push-based architecture Ansible Components...

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Cisco NX-OS: VXLAN and External Connectivity

By default: underlay – default VRF overlay – “tenant” VRF, hosts in VXLAN are isolated Border Leafs are used to connect the internal fabric to external networks. Not necessary a box, just configuration on the Leaf. It maintains the following routing control planes: MP-BGP L2VPN EVPN – inside VXLAN fabric “tenant” VRF BGP or IGP to external routes MP-BGP to BGP/IGP...

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Cisco NX-OS: VXLAN – vPC – Anycast

VxLAN and vPC Anycast VTEP Problem with VXLAN and vPC: in a vPC both vPC peers duplicate EVPN MAC/IP routes to spine RRs with other attributes equal, one vPC peer is always preferred for dual attached hosts (based on the normal BGP Best path selection) Result: egress traffic from vPC Member is load-balanced, but return ingress traffic is polarized Solution: Anycast VTEP...

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Cisco NX-OS: VXLAN Symmetric Routing

EVPN Integrated Routing and Bridging (IRB) has two options: Asymmetric IRB (increased ARP cache and CAM table sizes and control plane scaling issue) Symmetric IRB Symmetric IRB Ingress VTEP does both L2 and L3 lookup Egress VTEp does both L3 and L2 lookup => Bridge – Route – Route – Bridge L3 VNI should be configured on all VTEPS, L2 VNIs...