MPLS – Traffic Engineering (MPLS-TE) Options

MPLS, or Multiprotocol Label Switching, is a technique that enhances the speed and efficiency of data flow across complex networks. It operates by adding short path labels to network packets, directing them through a predetermined Label-Switched Path (LSP) rather than traditional IP-based routing. These labels contain all the forwarding information, allowing routers to forward packets based on the label rather than performing complex IP lookups. By simplifying the routing decision process, MPLS can reduce latency, optimize network performance, and enable quality-of-service (QoS) features that guarantee certain levels of bandwidth and prioritize critical applications like voice and video.

MPLS is widely used in service provider networks, supporting technologies like VPNs (Virtual Private Networks) and traffic engineering. In a typical MPLS setup, labels are assigned and stripped at the network’s edge, so the core network can process packets quickly without IP overhead. Additionally, MPLS is adaptable to various network protocols and media, enabling seamless interoperability across different types of infrastructure. By allowing network operators to manage traffic dynamically and reroute around congestion or failures, MPLS ensures greater reliability and robustness, making it a preferred choice for large-scale enterprise and ISP networks.

MPLS Traffic Engineering (MPLS-TE) is a technology that enhances the capabilities of MPLS to enable more granular control over traffic flow within a network. This is achieved by manipulating traffic paths to optimize resource usage, avoid congestion, and meet specific service requirements, like bandwidth guarantees or low latency. Here are key methods by which MPLS-TE can manipulate paths and traffic flow:

MPLS-TE Traffic manipulation options

Explicit Routing with Constraint-Based Routing (CBR)

  • Constraint-based routing allows MPLS-TE to create Label-Switched Paths (LSPs) that follow a specific path through the network, rather than relying on traditional routing protocols.
  • Explicit path setup enables network operators to define exact paths based on link attributes, resource availability, or even administrative preferences, avoiding congested or unreliable links.
  • Constraints can include bandwidth, latency, maximum hop count, and available resources.
! Define an explicit path list for the TE tunnel
Router(config)# ip explicit-path name Path_R1_R3
Router(config-ip-expl-path)# next-address 10.1.1.2  ! IP of Router2
Router(config-ip-expl-path)# next-address 10.1.2.2  ! IP of Router3

! Configure the TE Tunnel
Router(config)# interface Tunnel1
Router(config-if)# ip unnumbered Loopback0
Router(config-if)# tunnel mode mpls traffic-eng
Router(config-if)# tunnel destination 10.1.3.3     ! Destination (Router3)
Router(config-if)# tunnel mpls traffic-eng path-option 1 explicit name Path_R1_R3
Router(config-if)# tunnel mpls traffic-eng bandwidth 1000   ! Set bandwidth constraint
Router(config-if)# no shutdown

Traffic Engineering Database (TED)

  • The TED collects information on the state of the network, such as available bandwidth, link utilization, and link properties.
  • MPLS-TE uses the TED to make dynamic routing decisions based on real-time information, thus selecting paths that avoid congested areas and optimize resource use.
! Enable traffic engineering on OSPF
Router(config)# router ospf 1
Router(config-router)# mpls traffic-eng router-id Loopback0
Router(config-router)# mpls traffic-eng area 0

! Ensure interfaces participate in TE
Router(config)# interface GigabitEthernet0/1
Router(config-if)# ip router ospf 1 area 0
Router(config-if)# mpls traffic-eng tunnels

Resource Reservation with RSVP-TE

  • RSVP-TE (Resource Reservation Protocol with TE extensions) is used to signal and reserve resources along the selected path.
  • This protocol sets up traffic-engineered LSPs (TE LSPs) and reserves the necessary bandwidth to meet quality-of-service (QoS) requirements.
  • With RSVP-TE, MPLS-TE can ensure certain traffic flows (like voice or video) get dedicated resources, reducing packet loss and jitter.
! Enable RSVP globally
Router(config)# mpls traffic-eng tunnels
Router(config)# ip rsvp signaling hello

! Enable RSVP on each interface used by the MPLS-TE tunnel
Router(config)# interface GigabitEthernet0/1
Router(config-if)# ip rsvp bandwidth 10000 1000  ! Interface bandwidth in kbps, reserved bandwidth

! Configure an MPLS-TE tunnel with RSVP
Router(config)# interface Tunnel2
Router(config-if)# ip unnumbered Loopback0
Router(config-if)# tunnel mode mpls traffic-eng
Router(config-if)# tunnel destination 10.1.3.3
Router(config-if)# tunnel mpls traffic-eng bandwidth 2000
Router(config-if)# tunnel mpls traffic-eng path-option 1 dynamic
Router(config-if)# no shutdown

Fast Reroute (FRR)

  • Fast Reroute enables rapid path switching in case of a link or node failure, ensuring minimal disruption.
  • FRR pre-establishes backup LSPs so that traffic can be diverted almost instantaneously in case of an issue on the primary path, enhancing reliability and service continuity.
! Configure fast reroute on the tunnel interface
Router(config)# interface Tunnel2
Router(config-if)# mpls traffic-eng fast-reroute
Router(config-if)# tunnel mpls traffic-eng path-option 1 dynamic
Router(config-if)# no shutdown

Load Balancing and Path Diversity

  • MPLS-TE supports load balancing by distributing traffic across multiple LSPs. This is particularly useful for high-traffic routes that need more bandwidth than a single path can provide.
  • Path diversity ensures that critical data can be split across multiple paths, reducing the risk of a single point of failure and improving network redundancy.
Router(config)# interface Tunnel3
Router(config-if)# ip unnumbered Loopback0
Router(config-if)# tunnel mode mpls traffic-eng
Router(config-if)# tunnel destination 10.1.3.3
Router(config-if)# tunnel mpls traffic-eng path-option 1 dynamic
Router(config-if)# tunnel mpls traffic-eng path-option 2 explicit name Path_R1_R3
Router(config-if)# no shutdown

Bandwidth Guarantees and Traffic Prioritization

  • MPLS-TE can allocate bandwidth to specific traffic flows, ensuring certain types of traffic, like real-time or high-priority data, meet their QoS requirements.
  • Differentiated services (DiffServ) can be implemented within MPLS-TE, allowing traffic prioritization at the LSP level and ensuring high-priority traffic gets preferential treatment.
! Set bandwidth requirement for TE tunnel
Router(config)# interface Tunnel4
Router(config-if)# tunnel mode mpls traffic-eng
Router(config-if)# tunnel destination 10.1.3.3
Router(config-if)# tunnel mpls traffic-eng bandwidth 5000   ! 5000 kbps reserved
Router(config-if)# no shutdown

Administrative Policies and Affinity-Based Routing

  • Administrative policies (affinity or coloring) can be used to prefer or avoid certain links based on the type of traffic.
  • Affinity or link coloring allows paths to be marked for certain traffic types (e.g., customer A’s traffic can only use certain links), enabling more precise traffic segregation and adherence to SLA requirements.
! Define affinity on an interface (e.g., marking it with color 0x10)
Router(config)# interface GigabitEthernet0/2
Router(config-if)# mpls traffic-eng administrative-weight 0x10

! Set affinity for the tunnel
Router(config)# interface Tunnel5
Router(config-if)# tunnel mode mpls traffic-eng
Router(config-if)# tunnel destination 10.1.3.3
Router(config-if)# tunnel mpls traffic-eng path-option 1 dynamic
Router(config-if)# tunnel mpls traffic-eng attribute-flags affinity 0x10
Router(config-if)# no shutdown

Dynamic Path Computation with Path Computation Element (PCE)

  • The Path Computation Element (PCE) is a centralized network component that dynamically computes paths for MPLS-TE LSPs based on network-wide data.
  • PCE enhances scalability and efficiency in large networks by providing real-time, optimized path computation and reducing computational strain on routers.
! Enable PCEP on the router
Router(config)# pce
Router(config-pce)# address ipv4 10.1.4.4
Router(config-pce)# source Loopback0
Router(config-pce)# no shutdown

! Configure the tunnel to use PCE for path computation
Router(config)# interface Tunnel6
Router(config-if)# tunnel mode mpls traffic-eng
Router(config-if)# tunnel destination 10.1.3.3
Router(config-if)# tunnel mpls traffic-eng path-option 1 dynamic pce
Router(config-if)# no shutdown

 

These examples demonstrate basic configurations for MPLS-TE features. Advanced setups may require customizations based on network architecture, device capabilities, and specific application needs.

CML 2.7 – Getting started with Cisco Modeling Labs v2.7

Last weekend I decided to try Cisco’s Modeling Labs (CML). This is Cisco’s network virtualization platform comparable to GNS3 or EVE-NG. It replaced an older Cisco product called VIRL (Virtual Internet Routing Lab), offering more features and improved performance.
I have quite a lot of experience with both EVE-NG and GNS3, so I’m curious to see how CML will compare.

In this article we go over the following steps:

Getting started

I went with the option of installing CML on my ESXi server.
This installation will cover a fresh install on VMware ESXi using the CML .OVA file. 
Some useful links before we get started:

CML information:
https://www.cisco.com/c/en/us/products/cloud-systems-management/modeling-labs/index.html

CML Licensing:
https://learningnetworkstore.cisco.com/cisco-modeling-labs-personal/cisco-modeling-labs-personal/CML-PERSONAL.html

Software download:
https://software.cisco.com/download/home/286290254/type/286290305/release/CML-Personal%202.7.2

We start by downloading two files from the software website. We need both of these for the install.

    1. The server installation file (either the OVA of the ISO).
    2. The reference platform ISO (this contains the router images that are used in CML).

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350-501 Service Provider Core Resources


CCNP SPCOR 350-501 Official Cert Guide ( Release December 2024 )
https://www.amazon.com/CCNP-SPCOR-350-501-Official-Guide/dp/0135324807
https://www.ciscopress.com/store/ccnp-spcor-350-501-official-cert-guide-9780135324806

CCNP SPCOR 350-501 Official Cert Guide Premium (with practice tests)

https://www.ciscopress.com/store/ccnp-spcor-350-501-official-cert-guide-premium-edition-9780135324875

Segment Routing
Segment Routing in MPLS Networks: Transition from traditional MPLS to SR-MPLS with TI-LFA FRR
Segment Routing for Service Provider and Enterprise Networks

SPCOR Cisco study Materials
https://learningnetwork.cisco.com/s/learning-plan-detail-standard?ltui__urlRecordId=a1c3i000003OvP0AAK&ltui__urlRedirect=learning-plan-detail-standard

SPCOR Cisco Official Learning Matrix  
https://learningcontent.cisco.com/documents/marketing/exam-topics/CCNP_SP_v1.0_Learning_Matrix.xlsx

SPCOR Videocourses
Luc de Ghein’s MPLS Fundamentals:
https://www.oreilly.com/library/view/mpls-fundamentals/9780134675398/

Nick Russo’s pluralsight courses.
https://www.pluralsight.com/authors/nick-russo
https://www.pluralsight.com/courses/cisco-service-provider-spcor-350-501-intro-cert
https://www.pluralsight.com/courses/cisco-multiprotocol-label-switching-implementing

INE.com:
https://my.ine.com/Networking/learning-paths/83c88b88-9041-4079-b913-2bd0474dae26/service-provider-core-exam-350-501-spcor

INE Live Webinar: Understanding Inter-AS L3VPN – Option A/B/C
https://www.youtube.com/watch?v=wT0eQPMj2Ck

CBTnuggets:
https://www.cbtnuggets.com/it-training/cisco/ccnp-service-provider-core


SPCOR Unofficial Studyguide
https://ccnp-sp.gitbook.io/studyguide

This study guide reads as more of a lab workbook than a textbook. I would highly recommend labbing along with each section. Each article typically starts with some background information and theory on the topic. You will then see a “Lab” section that contains a topology diagram and a code block with startup configs, which you can use to quickly build your own lab and follow along.

SPCOR Cisco Live PDFs
https://red9.nl/ccnp-service-provider-350-501-spcor-study-materials/

The CCNP Service Provider v1.0 Learning Matrix for the 350-501 SPCOR training references a lot of Cisco Live presentations. Unfortunately almost all links are broken at the time of writing this post. I’ve been able to find all except one of the presentations from all over the internet from a mix of AD infested presentation sharing sites.
Here they are, straight up linked PDFs to save you from the waste of time

IOS-XR Workbook
https://www.fryguy.net/wp-content/uploads/2013/03/Cisco-IOS-XR-Introduction-Ver-1.pdf

Cisco Press Books/Video
https://www.ciscopress.com/store/ip-routing-on-cisco-ios-ios-xe-and-ios-xr-an-essential-9781587144233
https://www.ciscopress.com/store/mpls-fundamentals-9781587051975
https://www.ciscopress.com/store/troubleshooting-bgp-a-practical-guide-to-understanding-9781587144646
https://www.ciscopress.com/store/bgp-troubleshooting-livelessons-9780134582870
https://www.ciscopress.com/store/bgp-design-and-implementation-paperback-9781587144707
https://www.ciscopress.com/store/end-to-end-qos-network-design-quality-of-service-for-9780133116106
https://www.ciscopress.com/store/qos-for-ip-mpls-networks-9780133434996
https://www.ciscopress.com/store/layer-2-vpn-architectures-9781587051685

SPCOR Roadmap
https://learningnetwork.cisco.com/s/cisco-certification-roadmaps?tabset-4a075=a9b02
SPCOR V1.1 will go live on 20 september 2024.

 

 

A.I. generated network diagrams

Today I had some fun with A.I. trying to generate network diagrams.

I asked an untrained A.I. model to generate “a simple MPLS topology” for my study notes. While the image looked like a computer network it still had many incoherent additions.

For the second image I used the prompt “a diagram explaining the difference between MPLS P, PE and CE notes”.


It will be interesting to see if we can learn the model to generate better topologies and streamline documentation.

[QoL] Uploading files to Cisco TAC via CXD

Uploading files to a Cisco TAC case.

Have you ever needed to upload large (log)files from an appliance to a Cisco TAC?

Troubleshooting DNA-Center for example usually involves creating Root Cause Analysis (RCA) files which can be well over 1GB. After generating the files we have to copy them from the controller and either mail them to the case, or upload them via the webinterface with the Case File Uploader. Both of these options require additional steps of copying and transferring. 

Customer eXperience Drive.

There is an easier way to upload the files directly from the controller using the Customer eXperience Drive (CXD).

The Customer eXperience Drive (CXD) is a multi-protocol file upload service with no limitation on the uploaded file size. It allows Cisco customers with active Service Requests (SRs) to upload data directly to a case using a unique set of credentials created per SR. The protocols supported by CXD are natively supported by Cisco products which allows for uploading directly from Cisco devices to SRs.

You will need the following things;

  • Service Request Number
  • CXD Token

To generate the CXD Token complete these steps:

Step 1   Log in to SCM.
Step 2   Open the case you would like to get the upload token for.
Step 3   Click the Attachments tab.
Step 4   Click Generate Token. Once the token is generated it will be displayed next to the Generate Token button.

Uploading files using CURL

Once we have the SR number (SR60000000) and the token (aaaabbbbccccdddd) we can use that to upload directly from a controller. We can transfer the file with our SR credentials to https://cxd.cisco.com/home/ and the file will be automatically added to the case.

CURL without a proxy:

  • curl -T “[path/to/file]/[file]” -u 60000000:aaaabbbbccccdddd https://cxd.cisco.com/home/

CURL with a proxy:

  • curl -T “[path/to/file]/[file]” -x http://[proxy:8080] -u 60000000:aaaabbbbccccdddd https://cxd.cisco.com/home/

Sample Python Code to use the PUT API

Note that the following code assumes the file is stored in the same path you are running it from.

import requests
from requests.auth import HTTPBasicAuth
url = 'https://cxd.cisco.com/home/'
username = 'SR Number'
password = 'Upload Token'
auth = HTTPBasicAuth(username, password)
filename = 'showtech.txt'
f = open(filename, 'rb')
r = requests.put(url + filename, f, auth=auth, verify=False)
r.close()
f.close()
if r.status_code == 201:
    print("File Uploaded Successfully")

Enjoy your no limit uploads!

LAB IX – RIPv2 -> OSPF Case Study

Building a use case from the CCDP FLG:

Topology:

  • Each site has two links to their HQ (top) via WAN (Prio) and Internet ( backup ).
  • Internet and WAN connectivity goes over multipoint GRE tunnels to the sites with static NHRP mappings.
  • Cost of Internet links are increased so they’re used as backup links.
  • Backbone area configured over WAN and Internet

Building the LAB:

OSPF Design

Building the Backbone:

Adding the tunnel interface and NHRP mappings on the WAN Hub Router (R1):

And we have some routing on the Hubs:

[DC] Cloud Computing

Basic cloud computing

  • Essential Characteristics
    • Broad network access
    • Rapid elasticity
    • Measured Service
    • On-demand Self-service
    • Resource pooling
  • Service Models
    • SaaS – Software as a Service
    • PaaS – Platform as a Service
    • IaaS – Infrastructure as a Service
  • Deployment Models
    • Public
      • Provisitioned for open use by the general public
    • Private
      • Cloud for the exclusive use by a single organization
      • Managed by IT or thirdparty
      • on-premise or off-premise
    • Hybrid
      • Two or more cloud infrastructures combined
    • Community
      • Multiple organisations combined

What is an API

  • A precise specification written by providers of a service
  • You must follow the specification when using that service
  • An API decribes what functionality is available, how ti must be used and what formats it will accept as input or return as output

(more…)

[DC] ACI and APIC

ACI > Contructs

Tenant VDC
Context VRF
Bridge domain Subnet / SVI
EPG Broadcast domain / VLAN
Contract ACL
L2 External EPG 802.1Q trunk
L3 External EPG L3 Routed link

Fundamentals:

  • Open and Secure
  • Apps and Infrastructure
  • Physical and Virtual
  • On-Site and Cloud

Bringing up the Fabric:

  • Physical requirements
    • Power
    • Cabling + mgmt0
    • Rack and Stack
  • Power on/Connect to APICs
    • How many APICs
    • Fabric Name
    • Admin Password
    • Setup Fabric Network ( IP & VLAN)
  • Log into the APIC (HTTP out of band)
    • NTP
    • Route Reflectors
    • MGMT IP Fabric
    • Leaf and Spine Name/#

Fabric Discovery

  • Zero touch fabric, the controller does everything
  • APIC uses LLDP to get information about the leaf switches it’s connected to
  • First the leaf is dicovered and will be named (101)
  • Then the Spine is connected and named  (201)
  • Then the leafs are discovered (103,104)

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[DC] Datacenter Interconnects (DCI, OTV)

Distributed Data center Goals

  • Ensure business continuity
  • Distributed applications
  • Seamless workload mobility
  • Maximize compute resources

Challenges in traditional Layer 2 VPN:

  • Flooding Behavior
    • Unknown unicast for mac propagation
    • Unicast Flooding reaches all sites
  • Pseudo-wire Maintenance
    • Full mesh of Pseudo-wire is complex
    • Head-End replication is a common problem
  • Multi-Homing
    • Requires additional protocols and extends STP
    • Malfunctions impact multipe sites

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[DC] Nexus features config / commands

VDC Configuration

  • Show license usage
  • Show vdc
  • Show vdc membership
  • vdc DCC01
  • allocate resource command
  • limit-resource command
  • show run vdc
  • switchto vdc DCC01

FEX Configuration

  • Enable feature FEX
  • configure fex 100
  • interface e1/25
  • switchport mode fex-fabric
  • fex associate 100
  • show fex

VPC Configuration

  • feature vpc
  • vpc domain 100
  • peer-keepalive destination 10.10.10.2 source 10.10.10.1 vrf management
  • sh vpc
  • int po10
    • vpc peer-link
  • int e 1/25
    • channel-group 10 mode active
  • int po10
    • vpc 10

(more…)