How Does Internet Work

This is a short version without comments and explanations for those that need to get things done quickly without reading through my extensive waffle.

For detailed update procedure with all the explanations check extended article: “ISSU Upgrade of Cisco Catalyst 6880-X VSS cluster and its four 6800ia FEX extenders“

Let’s start!

1. Get the info on which IOS version is supported to be upgraded with ISSU

Google for ISSU or EFSU IOS upgrade support or use this Cisco doc “SX_SY_EFSU_Compatibility_Matrix1” to select supported IOS for ISSU upgrade from your current version.

2. Upload IOS to both Chassis

copy ftp://admin:[email protected]/c6880x-adventerprisek9-mz.SPA.151-2.SY7.bin bootdisk:

and same for slavebootdisk:

This is a description on how to deploy a Juniper LAB of 8 vMX routers and making a simple topology in VMware vSphere environment. vMX is Juniper’s virtual production router so this could be the same procedure for deploying vMX device in production except different number of routers and their interconnection with vSwitch setup.

Two VMs interconnected with VLAN801 – making one Juniper vMX router

As you might have seen from my previous post, I’m trying to get into Juniper configuration lately. One of the things that I needed is to set up a simple lab running Juniper vMX machines with multicast forwarding enabled.

It was a simple lab experiment with few commands on each device. As it turns out, being a Cisco fellow, each of those commands presented a complicated googling routine until the thing finally started to work.

Most time I spent configuring Virtual Machines and boot them properly, after that Juniper Configuration Guides were enough to make fist lab scenarios.

Googling went somewhat like this:

• How to set up Juniper vMX on Vmware ESXi 6.0 and interconnect 8 instances of vMX?
• How to configure Vmware network and vSwitches to make this work?
• How to configure VCE and VPE vMX Control and Forwarding plane VM communication?
• How to configure interfaces and map them to VMware vSwitch interfaces?
• How to configure Juniper eth interfaces, OSPF, Multicast with PIM Sparse mode?
• Why this does not work from the first try? Do I need vMX Evaluation licence to do that?
• What for …. does ‘tunnel-services statement on one or more online FPC and PIC’ mean?

…so when it actually finally worked, I decided to share it so you can have one post that would describe it from start all the way to VLC Multicast streaming.

I’m fairly new to Juniper CLI. For one of my first tries, I decided to make my life difficult by starting with multicast configuration on virtual vMX routers running as VMs on VMware ESXi.

It took a lot of investigation about some part of this configuration specially the tunnel interface which you will see below. I decided to put it here all in one place with the explanation of every step because Juniper documentation tends to assume that you know more than me. If that is not the case, this short description is for you.

Here’s how the topology looks like. I have 8 routers making this topology with the plan to source multicast streams from right to left, from PC 10.10.99.11 towards PC 10.10.98.11

Configuration

If a computer on local LAN network is turned off and administrator needs to do some regular maintenance on it, he will need to use Wake-On-LAN (WoL) to power the system up remotely.

Of course, network devices need to be configured to enable that kind of “magic” packet forwarding.

NIC cards on machines need to support WoL for this to work, but we don’t bother with this here..

WoL is sending “magic packets” to computer NIC card in order to start the system up. NIC which supports WoL is still receiving power when PC is turned off. NIC then keeps listening on the network for the magic packet and if received it will initialise the system boot process and power up the PC.

Magic packet is specially crafted network directed broadcast packet typically sent with connectionless UDP, port 7.

You would usually have a WoL server somewhere on you network which will be used to source magic packets. If you send magic packets across network segments (between VLANs or from some remote subnet), last router in the path, one having client subnet locally connected, needs to be configured with directed broadcast. The first router on the path, router with server subnet locally connected, should have ip helper configured pointing to directed broadcast IP address (in our case 172.19.1.255).

In our example below, both ip helper and directed broadcast are configured on the same L3 device since this is the only router connecting two subnets.

Directed broadcast on Cisco devices is off by default since IOS 12.0 and needs to be configured on specific subnets where WoL will be needed.

You need directed broadcast because PC which needs to be woken up is asleep and while asleep it will not have an IP nor it will respond to ARP. Only way to get some packets to that PC without an ARP resolution is by using local subnet L2 broadcast.

Furthermore, we can surely assume that your PCs are connected to L2 Access Switch. That switch will not know to which port is the PC connected while that PC is asleep. Only a Layer 2 broadcast (and unknown unicast) will be sent out all ports on a switch.

(Part I) Network Virtualization

This is the first part in the series of posts dedicated to network virtualization and path isolation.

Virtualization is a technique of simulating a hardware device by using software, usually on standard x86 CPU based servers. Hardware devices that are being virtualized are (in the order from most common) servers, firewalls, switches and routers. Almost all devices that you can think of can be virtualized, we listed the most common ones used within network operations. By using virtualization, we are able to run multiple virtual instances (virtual contexts) of a device, in the same way like we would run “real” hardware devices. Each of these virtualized instances is, of course, running independently and usually operating with separate configuration, enabling separation by purpose. Virtual instances are usually running as multiple contexts on specialised, virtualization enabled device or as Virtual Machines (VMs) on a Hypervisor platform like VMWare of Hyper-V.

Network Virtualization is part of above explained virtualization. It is virtulization of networking devices. We are using network virtualization with VLANs on switches to enable multiple broadcast domains (LAN segments) to be connected on one single switch. We are doing the same thing on layer 3 with enabling the router to run multiple routing instances by implementing VRF configuration on it. With VRF we are splitting the router into multiple routers, with VLANs we are splitting switch into multiple switches. We are doing this with the use of software but only on specialized hardware devices that are virtualization enabled.

There are two network elements we can virtualize

Network virtualization can be as simple as running firewall on a VMWare host. In this case we are just skipping the usage of real hardware appliance for firewalling task.

Things can get more complex with requirements for path isolation. Different categories of traffic then need to use same physical devices and their interconnections and have complete data communication isolation between them. Here we are in a situation where we will need to virtualize not only the above mentioned firewall but also router forwarding plane and interconnections between network devices.

VRF enables the router to run more “virtual” instances of routing and forwarding table. VLANs separate switch port groups into separate broadcast domains/isolated segments. Firewall can have trunk link with subinterfaces of which each one is separate zone forwarding traffic for one router VRF. Image on top shows three different isolated paths which are forwarded through same devices/interconnections. Below, physical topology is shown.

Ok that’s it! We can not only virtualize network devices but the paths between them to. Let’s see what that means.

As you can see from my article list, I’m going through some VRF configuration in the last few weeks 🙂

I ran into this today and it sounded interesting enough to share it with you. The issue with TFTP IOS image copy to flash when having all interfaces in specific VRF and no interface in Global Routing Table.

Long story short, you kick in this command for normal IOS download to the router:

R1#copy tftp://10.10.10.11/c890-universalk9-mz.154-3.M5.bin flash:
Destination filename [c890-universalk9-mz.154-3.M5.bin]? 
Accessing tftp://10.10.10.11/c890-universalk9-mz.154-3.M5.bin...
%Error opening tftp://10.10.10.11/c890-universalk9-mz.154-3.M5.bin (Timed out)

…and it isn’t working of course.

(Part II) Virtual Routing and Forwarding

This is the second part in the series of posts dedicated to network virtualization and path isolation.

Ever needed one extra router? It’s possible to split the router into more logical routers by using VRF. How? Here’s how!

Virtual Routing and Forwarding or VRF allows a router to run more that one routing table simultaneously. When running more routing tables in the same time, they are completely independent. For example, you could use overlapping IP addresses inside more VRFs on the same router and they will function independently without conflict (You can see this kind of overlap in the example below). It is possible to use same VRF instance on more routers and connect every instance separately using VRF dedicated router port or only a sub-interface.

You can find VRFs to be used on ISP side. Provider Edge (PE) routers are usually running one VRF per customer VPN so that one router can act as a PE router for multiple Customer Edge (CE) routers even with more customers exchanging the same subnets across the VPN. By running VRF per customer, those subnets will never mix in-between them.

VRFs are used to create multiple virtual routers from one physical router.

Every VRF is creating his own Routing table and CEF table, basically a separate RIB and FIB.