Book Table of Contents

AWS Networking - Part VI: Subnet to Route Table Association

At this phase, we have attached subnets to their respective Availability Zones. Next, we will create subnet-specific route tables for both Public and Private subnets.

Figure 1-25: VPC Subnets: Select VPC.

 

AWS Networking - Part V: Create Subnet Using AWS Console

When we have created a new VPC, we can start adding subnets to it. We are going to create two subnets. Subnet 10.10.0.0/24 is a Public Subnet in Availability Zone eu-west2c, where we later add an Internet GW. Subnet 10.10.0.0/24 is a Private Subnet in Availability Zone eu-west2a that will use a NAT GW for uni-directional Internet access.

Figure 1-18: VPC Route Table: Routes.

AWS Networking - Part IV: Create VPC Using the AWS CloudFormation

The focus of this section is to show how we can create a VPC using AWS CloudFormation service. Figure 1-12 shows our example AWS CloudFormation Templates. Its first section, AWSTemplateFormatVersion, specifies the template language format. At the time of writing, 2010-09-09 is the latest and only valid version. We can use the Description section to describe our template. Note that it must follow the AWSTemplateFormatVersion Section. AWSTemplateFormation-Version and Description are optional sections. The Resources section specifies the actual AWS resources and their properties. Each AWS resource is identified with a logical name. I have given the logical name NwktVPC for our example VPC. We can use resource-specific logical names for defining dependencies between resources. For example, when adding the AWS::EC2::Subnet resource to our template, we assign the VpcId value by calling it from the AWS::EC2::VPC resource using !REF intrinsinc function. I will explain the process in the Subnet section later. The resources and their properties are defined under logical names. The Resources section is the only required section in AWS CloudFormation-Template. AWS CloudFormation Templates are identified by using Stack Names in AWS Cloud Formation. Our example Stack Name is MyNetworkStack.

Figure 1-12: AWS CloudFormation: VPC.

AWS Networking - Part III: VPC Verification Using AWS CLI

 

VPC Verification Using AWS CLI

We can verify our VPC configuration by using AWS CLI. Example 1-1 shows the output for command aws ec2 describe-vpc in JSON format. This command lists all our VPC resources with their properties. The first one is the newest VPC NVKT-VPC-01, and the second one is the default VPC which I have named DFLT-VPC. The first VPC gets ordinal zero [0], and the second VPC gets number one [1]. Note that ordinal numbers are not shown in the output. VPC properties describe the VPC-specific CIDR Block, DHCP Options, VPC Identifier, Owner Id, CIDR Block Association, and Tags.

 

aws ec2 describe-vpcs

{

    "Vpcs": [

        {

            "CidrBlock": "10.10.0.0/16",

            "DhcpOptionsId": "dopt-09217361",

            "State": "available",

            "VpcId": "vpc-04ef72cc79a73f82e",

            "OwnerId": "123456654321",

            "InstanceTenancy": "default",

            "CidrBlockAssociationSet": [

                {

                    "AssociationId": "vpc-cidr-assoc-0379c0e3e854f43ff",

                    "CidrBlock": "10.10.0.0/16",

                    "CidrBlockState": {

                        "State": "associated"

                    }

                }

            ],

            "IsDefault": false,

            "Tags": [

                {

                    "Key": "Name",

                    "Value": "NVKT-VPC-01"

                }

            ]

        },

        {

            "CidrBlock": "172.31.0.0/16",

            "DhcpOptionsId": "dopt-09217361",

            "State": "available",

            "VpcId": "vpc-cfbac1a7",

            "OwnerId": "123456654321",

            "InstanceTenancy": "default",

            "CidrBlockAssociationSet": [

                {

                    "AssociationId": "vpc-cidr-assoc-89d487e1",

                    "CidrBlock": "172.31.0.0/16",

                    "CidrBlockState": {

                        "State": "associated"

                    }

                }

            ],

            "IsDefault": true,

            "Tags": [

                {

                    "Key": "Name",

                    "Value": "DFLT-VPC"

                }

            ]

        }

    ]

Example 1-1: AWS CLI: Retrieve VPC Information.

We can use filters for retrieving information only from some specific resources. The command aws ec2 describe-vpcs --filters Name=tag:Name,Values=NVKT-VPC-01 shows VPCs where we have attached the Key/Value pair Name/NVKT-VPC-01.

 

aws ec2 describe-vpcs --filters Name=tag:Name,Values=NVKT-VPC-01

{

    "Vpcs": [

        {

            "CidrBlock": "10.10.0.0/16",

            "DhcpOptionsId": "dopt-09217361",

            "State": "available",

            "VpcId": "vpc-04ef72cc79a73f82e",

            "OwnerId": "123456654321",

            "InstanceTenancy": "default",

            "CidrBlockAssociationSet": [

                {

                    "AssociationId": "vpc-cidr-assoc-0379c0e3e854f43ff",

                    "CidrBlock": "10.10.0.0/16",

                    "CidrBlockState": {

                        "State": "associated"

                    }

                }

            ],

            "IsDefault": false,

            "Tags": [

                {

                    "Key": "Name",

                    "Value": "NVKT-VPC-01"

                }

            ]

        }

    ]

}

Example 1-2: AWS CLI: Retrieve VPC Information.

We can also query resource-specific information using the command aws ec2 describe-vpcs --query "Vpcs[0]". The zero within square brackets after the resource Vpcs identifies the ordinal number of a resource. In our example, VPC NVKT-VPC-01 is the first one, and it has an ordinal number zero.

 

aws ec2 describe-vpcs --query "Vpcs[0]"

{

    "CidrBlock": "10.10.0.0/16",

    "DhcpOptionsId": "dopt-09217361",

    "State": "available",

    "VpcId": "vpc-04ef72cc79a73f82e",

    "OwnerId": "123456654321",

    "InstanceTenancy": "default",

    "CidrBlockAssociationSet": [

        {

            "AssociationId": "vpc-cidr-assoc-0379c0e3e854f43ff",

            "CidrBlock": "10.10.0.0/16",

            "CidrBlockState": {

                "State": "associated"

            }

        }

    ],

    "IsDefault": false,

    "Tags": [

        {

            "Key": "Name",

            "Value": "NVKT-VPC-01"

        }

    ]

}

Example 1-3: AWS CLI: Retrieve VPC Information.

If we want to see only some specific resource properties, we can add the properties after the resource, separated by a dot. Example 1-4 shows how we can see the CIDR Block Association for VPC NVKT-VPC-01 (ordinal zero).

 

aws ec2 describe-vpcs --query "Vpcs[0].CidrBlockAssociationSet"

[

    {

        "AssociationId": "vpc-cidr-assoc-0379c0e3e854f43ff",

        "CidrBlock": "10.10.0.0/16",

        "CidrBlockState": {

            "State": "associated"

        }

    }

]

Example 1-4: AWS CLI: Retrieve CIDR (Properties) Association to VPC (Resource).

We can change the output representation from the JSON to table by using the option --output table. The table output is a good choice when we create documentation about VPCs. Note that you can use this option with all other commands too.

 

aws ec2 describe-vpcs --query "Vpcs[0].CidrBlockAssociationSet" --output table

 

------------------------------------------------------

|                    DescribeVpcs                    |

+-----------------------------------+----------------+

|           AssociationId           |   CidrBlock    |

+-----------------------------------+----------------+

|  vpc-cidr-assoc-0379c0e3e854f43ff |  10.10.0.0/16  |

+-----------------------------------+----------------+

||                  CidrBlockState                  ||

|+------------------+-------------------------------+|

||  State           |  associated                   ||

|+------------------+-------------------------------+|

 

Example 1-5: AWS CLI: Retrieve CIDR Association to VPC – Table Output.

AWS Networking - Part II: Create VPC - AWS Console

The first thing to do when we create a VPC is to log in to the AWS console. Then we select the AWS Region where we want to launch our VPC. We are going to use VPC Region Europe (London) eu-west-2. As the last step, we give the name to VPC and associate a CIDR block 10.10.0.0/16 to it.

Figure 1-3: Virtual Private Cloud (VPC) – Example VPC.

AWS Networking - Part I: Virtual Private Cloud (VPC) Introduction

AWS Virtual Private Cloud (VPC) is a virtual network for Amazon Elastic Cloud Compute instances (EC2) within AWS Region. AWS Regions, in turn, belongs to the global AWS Cloud environment. Each AWS Region consists of three or more physical data centers, Availability Zones (AZ). At the time of writing, Seoul and Tokyo have four, and Northern Virginia has six AZs. All other regions have three AZs. VPC spans over regional AZs but not between AWS Regions. In other words, VPCs are region-specific virtual networks. 

A VPC has to have a CIDR (Classless Interdomain Routing) IP block attached to it. The VPC CIDR defines the IP range that we can use when creating subnets to VPC. CIDR range is VPC specific and can overlap with other VPC’s CIRD range. If there should be VPC-to-VPC inter-connection, VPC CIDR IP ranges have to be unique per VPC. 

We can allocate subnets for EC2 instances from the VPC’s CIDR range. Subnets are AZ-specific, and they can’t be span from one AZ to another. Subnets are classified either as Public Subnets or Private Subnets. Public Subnet has a route to Internet GW (Internet Gateway) in its Routing Table (RT). EC2 instances launched in a Public Subnet have to have a public IPv4 address in order to have an Internet connection. Note that IPv6 addresses are always assigned from the public address space. EC2 launched in a Private Subnet doesn’t need a public IPv4 address, they can have an Internet connection through the NAT GW. To allow Internet connection to EC2 instances in Private Subnet, we need to add a route to NAT GW into the Private Subnet Routing Table. We can allow a stateful egress-only Internet connection for EC2 instances with IPv6 addresses in Private Subnet by using Egress-Only Internet GW. This way EC2 instance has an Internet connection but hosts on the internet can’t initiate a connection to EC2. IP connectivity between EC2 instances within VPC is established between private IP address even if one of the EC2s is attached to Public Subnet and has a Public IP address. VPC has a main Routing Table that is used with subnets which we don’t define subnet-specific RT.

Each VPC also has a default Network Access Control List (NACL). The default NACL is bind to all subnets in VPC by default. NACL is stateless by nature, traffic to and from the subnet has to be allowed in both inbound and outbound directions. The default NACL allows all ingress/egress traffic.

Figure 1-1 illustrates our example VPC and its relationship to AWS Availability Zones, AWS Regions, and AWS Account. When we create VPC, we first have to log on to our AWS account. Next, we select an AWS Region, in our case Europe (London) eu-west-2. Then we choose Availability Zones for subnets. In our case, network 10.10.0.0/24 is a Public Subnet in the AZ eu-west-2c, and network 10.10.1.0/24 is a Private Subnet in the AZ eu-west-2a. As the last step, we create subnet-specific Routing Tables where we can later add subnet-specific routes.

Figure 1-1: Virtual Private Cloud (VPC) Basic Building Blocks.

LISP - OMP - BGP EVPN Interoperability - Part VIII: LISP, OMP, and BGP EVPN Comparison

 

IP reachability

 

Every Overlay Network solution requires IP reachability between edge devices via Underlay Network. This section explains the basic routing solution in Underlay Network from Campus Fabric, SD-WAN, and Datacenter Fabric perspectives. Figure 7-1 illustrates the IP reachability requirements for Campus Fabric, SD-WAN, and Datacenter Fabric.

Figure 7-1: IP Reachability Requirements.

 

LISP - OMP - BGP EVPN Interoperability - Part VII: End-to-End Data-Plane Operation

 

Introduction

 

This chapter introduces Data-Plane operation and explains how the data packets from EP3 (IP 172.16.30.3) in Datacenter Fabric are forwarded via SD-WAN to EP1 (IP 172.16.100.10) in Campus Fabric. (1) EndPoint3 sends the ICMP Request packet to its gateway switch Leaf-11. Leaf-11 makes routing decisions based on the VRF NWKT routing table. Before forwarding the packet, Leaf-11 adds a VXLAN header where it uses L3VNI 10077. It also sets the outer IP header where it uses the Border-Leaf-13 tunnel interface’s IP address 192.168.50.13 as a destination. Spine-1 routes the packet to Border-Leaf-13 based on the outer IP address. Border-Leaf-13 notices that the destination IP address of the received IP packet belongs to its’s NVE1 tunnel interface. It removes the outer IP header and based UDP destination port it notices that this is VXLAN encapsulated packet. It knows that L3VNI 10077 belongs to VRF NWKT. It strips off the VXLAN header and routes the packet to vEdge-2. The ingress interface towards DC in vEdge-2 belongs to VPN 10. vEdge-2 consults its routing table. Based on it, vEdge-2 constructs tunnel headers and sends ICMP Request to vEdge-1 via Public-Internet using MPLS Label 1003 as a VPN identifier. Routers in Internet routes packet based on the outer destination IP address. When vEdge-1 receives the packet, it notices that the destination IP address is its’ Public IP address. It first removes the outer IP header. Then it checks the tunnel header. Based on the Label value 1003, it knows that packet belongs to VPN 10. It consults the VPN 10 RIB and routes the packet to Border-PxTR-13. The ingress interface on Border-PxTR-13 belongs to VRF 100_NWKT that belongs to LISP Instance 100. It checks the Instance 100 specific LISP mapping in order to know how it should route the packet. The LISP mapping Database does not contain the information because this is the first packet to destination 172.16.100.10. Border-PxTR-13 sends a LISP Map-Request message to MapSrv-22, which replies with a LISP Map-Reply message, where it describes the RLOC of Edge-xTR-11 that has registered the IP address 172.16.100.10. I have excluded the Map-Request/Reply processes from figure 6-1 to keep the figure simple. Border-Leaf-13 encapsulates the ICMP Request packet with a tunnel header. It sets the Instance-Id 100 on the VXLAN header and adds the outer IP header where it uses the Edge-xTR-11’s IP address 192.168.0.13 as a destination address. Core-1 routes the packet to Edge-xTR-11 based on the outer IP header destination address. Edge-xTR-11 processes the ingress IP packet because the destination IP address belongs to it. Based on the destination UDP port 4789, it knows that the following header is a VXLAN header. Edge-xTR-11 knows that the LISP Instance-Id 100 is bind to BD 100. Because Edge-xTR-11 has an L3 interface in BD 100, it resolves the MAC address for the IP address 172.16.100.10 from the ARP table and the egress interface for the MAC from the MAC address table. EP1 processes the ICMP Request packet and sends the ICMP Reply to EP3.

Figure 6-1: End-to-End Data-Plane Operation.

 

LISP - OMP - BGP EVPN Interoperability - Part VI: LISP Control-Plane - Registering External IP Prefixes

 

Introduction

 

This chapter introduces how Border-PxTR-13 registers the external IP prefix 172.16.30.0/24 received as a BGP update from vEdge-1 to MapSrv-22 using LISP Map-register messages. Chapter 2 explains the LISP RLOC-to-EID mapping process in detail so this chapter just briefly recaps the operation. Figure 5-1 illustrates the overall process. vEdge-1 sends a BGP Update message where it describes the NLRI for prefix 172.16.30.0/24. Border-PxTR-13 first imports the information into the LISP processes. Next, it sends a LISP Map-Register message to MapSrv-22. In addition to IP prefix information, the Map-Register message carries Locator Record information that describes the destination IP address used in the outer IP header (tunnel header) when devices route IP packets towards the advertised subnet.  

Figure 5-1: Overall Control-Plane Operation: OMP to LISP

LISP - OMP - BGP EVPN Interoperability - Part V: BGP EVPN MAC Advertisement Route (Type 2).

 

Introduction

 

We have seen in previous chapters how the IP address 172.16.100.10 assigned to EP1 is advertised within the LISP domain and advertised as an aggregate route all the way down to Leaf-11 in the BGP EVPN domain. This chapter first explains how the EP3 ‘s IP address 172.16.30.3 is first advertised by Leaf-11 as BGP EVPN MAC Advertisement Route (Route-Type 2) via Spine-1 to Border-Leaf-13. Next, you will learn how Border-Leaf-13 advertises the aggregate route 172.16.30.0/24 to SD-WAN edge device vEdge-2. The last section briefly shows how the routing information is propagated over the SD-WAN. The BGP EVPN NLRI MAC Advertisement Route carries to MPLS Labels which identifies L2VN (10000) and L3VN (10077). In our example, VLAN 10 is part of the VRF NWKT and it is attached to L2VN 10000. L3VNI for VRF NWKT is 10077. 

Figure 4-1: Overall Control-Plane Operation: BGP EVPN to OMP to LISP.

LISP - OMP - BGP EVPN Interoperability - Part IV: BGP EVPN IP Prefix Route (Type 5)

Introduction

 

Figure 3-1 shows the Overlay Network Control-Plane interaction. Edge-xTR-11 registers reachability information (IP address and location) of EP1 to MapSrv-22. MapSrv-22 stores the information into the Mapping database and then installs it to RIB. Then MapSrv-22 exports the information to the BGP process and sends BGP Update using VPNv4 address format to Border-PxTR-13. Border-PxTR-13 imports NLRI into BRIB and RIB. Then it sends BGP Update to the local SD-WAN edge device vEdge-1. After importing the received information into BRIB and RIB, vEdge-1 exports the information to the OMP process and advertises it over a DTLS connection to vSmart (SD-WAN Control-Plane node). vSmart, in turn, advertises information to remote SD-WAN device vEdge-2. After importing the received information into the RIB, vEdge-2 exports the information to the BGP process and sends BGP Update to Border-Leaf-13. Border-Leaf-13 installs the information into BRIB and RIB. Next, Border-Leaf-13 sends BGP Update message using EVPN route type 5 (IP Prefix Route) to its iBGP peer Spine-1 (BGP Route-Reflector) using auto-generated Route-Target 65030:10077. Spine-1 forwards the BGP Update to Leaf-1, which imports the information into L3VNI used with VRF NWKT and installs the route into the VRF NWKT RIB.

Figure 3-1: Overall Control-Plane Operation.

LISP - OMP - BGP EVPN Interoperability - Part III: SD-WAN Control Plane

 Introduction

 

Figure 2-1 shows the Control Plane operation when host EP1 using IP 172.16.100.10/32 joins the network. In the previous chapter, we saw how Edge-xTR-11 learned the IP address and registered it to MapSrv-22 by using the LISP Map-register Message where the Instance-Id 100 represents Virtual Network-Id (VN-Id). MapSrv-22, in turn, advertised the NLRI to Border-PxTR-13 as BGP VPNv4 Update message where extended community RT 1:100 (=VN-Id) is used as a kind of VPN identifier (BGP VPNv4 route import/export policy is based on RT value). This chapter first explains how Border-PxTR-13 sends BGP IPv4 Update message to local SD-WAN device vEdge-1. The eBGP peering between Border-PxTR-13 and vEdge1 is VRF based and BGP updates over it don’t carry any VN-Id. vEdge-1 imports the routing information from BRIB to RIB. Then it advertises the routing information by using OMP (Overlay Management Protocol) to the SD-WAN centralized Control Plane vSmart over the DTLS tunnel using System-IP as an originator-Id and VPN label 1003 as a VN-Id. vSmart forwards this update to SD-WAN device vEdge-2 located in Datacenter. vEdge-2 installs the route into the routing table. After that, it exports the routing information from the RIB to the BGP process and sends the BGP IPv4 Update message to Border-Leaf-13 over VRF NWKT eBGP peering without VN-Id.

Figure 2-1: Overall Control-Plane Operation.

LISP - OMP - BGP EVPN Interoperability - Part II: VPNv4 Update from Control Plane to Border-PxTR

 

The previous chapter describes how Edge-xTR-11 used LISP Map-Register message to advertise EID-to-RLOC information to MapServ-22. It also explained how MapSrv-22, as a role of Mapping Server, stores the information into Mapping Data Base. MapSrv-22 is also Map-Resolver. This means that when it receives the LISP Map-Request message from the xTR device, it will respond with a Map-Reply message. If MapSrv-22 knows the EID-to-RLOC mapping, it places this information into the Map-Reply message. If MapSrv-22 doesn’t have mapping information, it instructs requesting xTR to forward traffic to its Proxy-xTR. This, however, is not the case in our example. What we want to do is advertise the EP1 reachability information to Border-PxTR. In order to do that, we need to a) export EID-to-RLOC information from the Mapping Data Base to instance-specific VRF_100 RIB. Then we can advertise it by using BGP and because we want to include virtual network identifier into update we use MP-BGP VPNv4 because there we have Route Target Attribute. The next sections describe the process in detail.

 

Phase 1: Map-Server - RIB Update

 

LISP Map-Server doesn’t install EID-to-RLOC mapping information from the Mapping Database into a RIB by default. To do that we need to export the information from the LISP Mapping DataBase to RIB by using the LISP Instance-specific command route-export site-registrations.  Example 1-6 illustrates the update process. Example 1-7 shows the RIB entry concerning EP1 IP address 172.16.100.10/32 in VRF 100_NWKT. Due to redistribution, the route is shown as directly connected, via Null0. If you take a look at the timestamps in example 1-6 and compare it to timestamps in example 1-3, you will see that the RIB update happens right after the unreliable EID-to-RLOC registration process.

 Complete device configuration can be found in chapter 1 Appendix 1.

Figure 1-10: EID-to-RLOC information from LISP to RIB.

 

LISP - OMP - BGP EVPN Interoperability - Part I: LISP EID-to-RLOC Registration

I have written a couple of books about Network Virtualization Overlay over Layer 3 (NVO3). My first book was about Datacenter network virtualization based on BGP L2VPN EVPN. After that, I wrote a book about Campus networks based on LISP. In my latest book, I introduced the Cisco SD-WAN solution running OMP in Control-Plane. I wanted to write one more book where I combine these three different NVO3 solutions. I haven’t used pictures in the “About This Book” section in my previous books but now I decided to do that because one picture tells more than 1000 words. The figure below combines these three NVO3 solutions and illustrates what is needed to have IP connectivity between EP1 in the LISP domain and EP2 in the BGP EVPN domain. After reading this book you should be able to understand the processes of how IP reachability information about local hosts are advertised from the LISP domain over the SD-WAN to BGP EVPN domain and another way around. I wanted to keep this complex solution as simple as possible. That is why I didn’t include any redundancy.

Cisco SD-WAN

Table of Contents

Chapter 1: Setting Up On-Prem Controllers 1

    Introduction 1

    Configuring IOS-XE Certification Server 2

    Enabling HTTP Server and NTP 2

    Certificate Server Configuration 2

    vManage Configuration 4

    System Information 6

    VPN Configuration 6

    Certification enrollment 8

    vBond Initial Configuration 15

    System Information 17

    VPN Configuration 18

    Certification enrollment 19

    vSmart Initial Configuration 25

    System Information 26

    VPN Configuration 26

    Certification enrollment 27

    Control Connection Verification 33

SD-WAN Part V: Hub and Spoke with Restrected Spoke Sites

 

 

Introduction

 

Cisco Viptela SD-WAN solution builds a full-mesh topology between vEdge devices by default when there are no Control Policies implemented. This means that vEdges tries to build an IPSec/GRE tunnel to every reachable TLOC public IP addresses no matter which site or color (transport network) TLOCs belong to. We have already change the default behavior by using the restrict option (chapter 2) under tunnel interfaces. In this way, tunnels are only established between TLOCs belonging to the same color. In this chapter, we are going to create a Hub and Spoke topology by implementing a Control Policy where the vSmart advertises TLOC/OMP routes from site 30 to sites 10 and 20 and TLOC/OMP routes from sites 10 and 20 to site 30. vSmart doesn’t advertise TLOC/OMP routes between sites 10 and 20. Site 10 and 20 will be our Branch/Remote sites and site 30 will be the Hub/DataCenter site.

 

Figure 5-1 recaps the operation of the Overlay Management Protocol (OMP). vEdge1 in site 10 advertises TLOC route advertisement to vSmart where it describes its System Id, transport color, and encapsulation method as well as Public/Private IP and restricts attributes (among several other attributes). vSmart forwards TLOC routes received from vEdge1 to both vEdge2 (site 20) and vEdge3 (site 30). vEdge1 also advertises OMP routes where it describes the reachability information about its local subnet 172.16.10.0/24 bound to VPN10.

Figure 5-1: TLOC Route advertisement.