Underlay

In this Community Roundtable episode, returning guests Russ White and Nick Russo start our three part deep dive into the Border Gateway Protocol, or BGP, with a look at terminology, how peer relationships form, the differences between internal and external BGP, and scaling techniques.

 

Show Links

https://tools.ietf.org/html/rfc4271

https://www.ietf.org/rfc/rfc1771.txt

http://bgp.us/

 

Show Notes

Overview

• BGP is an external gateway protocol used widely in both the public internet and with enterprise organizations
• BGP is the only external gateway protocol and is traditionally used primarily to connect networks to other networks
• BGP was built primarily for policy propagation to provide reliability, scalability, and control
• BGP v4 is created which is the base version we still use today though updated over the year

 

Terminology

• Devices running BGP are called speakers
  • A connection between two speakers is called a peering session
  • The two speakers are often called peers or neighbors
• Network Layer Reachability Information is a key term to remember — NLRI
  • Address Families (AFs) carry NLRIs for different topologies and different kinds of reachability information (v4, v6, ethernet, mpls, etc.
• Autonomous System–a set of bgp speakers contained within a single administrative domain (with some rather loose definition of an administrative domain here)

 

Forming Neighbor Relationships

• Runs over TCP
• Relies on TCP for flow control, three way handshake, mtu discovery, reliable transport
• Because of this, there is nothing like a DR/DIS/etc. — it’s a one-to-one peering
• This can cause issues with large scale peering
• These issues are normally solved by sending multiple copies of the same packet to each neighbor — peer groups

 

iBGP vs eBGP Overview

• iBGP is not a policy edge
• All iBGP speakers are supposed to appear to have a consistent policy from outside the AS
• eBGP is not really a routing edge, but rather a policy edge
• The idea is to allow multiple operators to run their networks without interference from peering operators
• This is not entirely “clean,” but it’s the goal
• Speakers send all routes to eBGP peers
• Speakers only send eBGP learned routes to iBGP peers
• This is because BGP relies on the AS path to prevent loops; there is no AS Path within an AS!
• How iBGP and eBGP differ in next-hop processing
• eBGP multi-hop designs (also discuss the “TTL misunderstanding”)
  • Multiple paths with a single next hop for load sharing

 

iBGP scaling techniques

• Route Reflectors
  • RR: regionalization matters sometimes (not always), route deflection
  • MPLS is a natural solution to this, for VPN and global transport
  • RR’s add an AS Path within the AS — the cluster list
  • This allows BGP speakers to send routes learned from an iBGP speaker to another iBGP speaker
  • The RR problem is the routes are not always optimal — hence add paths, optimal route reflection
  • Combination of RRs and direct iBGP sessions → optimal routing, since RRs sometimes hide topology. Generally easier than add-paths, ORR, and other techniques since you just n

In this Community Roundtable episode, returning guests Russ White and Nick Russo start our three part deep dive into the Border Gateway Protocol, or BGP, with a look at terminology, how peer relationships form, the differences between internal and external BGP, and scaling techniques.

 

Show Links

https://tools.ietf.org/html/rfc4271

In this episode of History of Networking, Alistair Woodman joins us to discuss the beginnings of commercial VoIP including a look at early protocols, CTI and the early days of ATM versus Frame-Relay versus IP.

Outro Music:

Danger Storm Kevin MacLeod (incompetech.com)

Licensed under Creative Commons: By Attribution 3.0 License

http://creativecommons.org/licenses/by/3.0/

In this episode of History of Networking, Alistair Woodman joins us to discuss the beginnings of commercial VoIP including a look at early protocols, CTI and the early days of ATM versus Frame-Relay versus IP.

Alistair Woodman Guest Russ White Host Donald Sharp Host Phil Gervasi Host Jordan Martin Host

Outro Music:
Danger Storm Kevin MacLeod (incompetech.com)
Licensed under Creative Commons: By Attribution 3.0 License
http://creativecommons.org/licenses/by/3.0/

The post History Of Networking – Alistair Woodman – VoIP appeared first on Network Collective.

Whether it’s a single GRE tunnel or a full Datacenter fabric, network overlays have played significant role in empowering network engineers to implement policy beyond simple IP reachability. In episode 16 of Network Collective we take a broad look at the types of overlays available to use in our networks, why you might want to implement an overlay, and some of the things to watch out for when employing overlay networking. Joining the NC hosts are two excellent guests: Ron Fuller, currently an SE at VMware on the NSX product team, and Warren Jackson, Technical Architect at WWT with a focus on SD-WAN technology.

Outro Music:

Danger Storm Kevin MacLeod (incompetech.com)

Licensed under Creative Commons: By Attribution 3.0 License

http://creativecommons.org/licenses/by/3.0/

Whether it’s a single GRE tunnel or a full Datacenter fabric, network overlays have played significant role in empowering network engineers to implement policy beyond simple IP reachability. In episode 16 of Network Collective we take a broad look at the types of overlays available to use in our networks, why you might want to implement an overlay, and some of the things to watch out for when employing overlay networking. Joining the NC hosts are two excellent guests: Ron Fuller, currently an SE at VMware on the NSX product team, and Warren Jackson, Technical Architect at WWT with a focus on SD-WAN technology.

Ron Fuller Guest Warren Jackson Guest

In this episode of History of Networking on Network Collective, Roland Dobbins from Arbor Networks joins us to talk about his role in mitigating distributed denial of service (DDoS) attacks on the internet.

Roland Dobbins Guest Russ White Host Donald Sharp Host Eyvonne Sharp Host

Outro Music:
Danger Storm Kevin MacLeod (incompetech.com)
Licensed under Creative Commons: By Attribution 3.0 License
http://creativecommons.org/licenses/by/3.0/

The post History Of Networking – Roland Dobbins – DDoS appeared first on Network Collective.

In this episode of History of Networking on Network Collective, Roland Dobbins from Arbor Networks joins us to talk about his role in mitigating distributed denial of service (DDoS) attacks on the internet.

Outro Music:

Danger Storm Kevin MacLeod (incompetech.com)

Licensed under Creative Commons: By Attribution 3.0 License

http://creativecommons.org/licenses/by/3.0/

In this Off The Cuff episode of Network Collective, recorded live at the SDxE conference in Austin, TX, the panel discusses the current state of network disaggregation, whitebox switching, and where the disaggregated model makes sense in your network.

 

Outro Music:

Danger Storm Kevin MacLeod (incompetech.com)

Licensed under Creative Commons: By Attribution 3.0 License

http://creativecommons

In this Off The Cuff episode of Network Collective, recorded live at the SDxE conference in Austin, TX, the panel discusses the current state of network disaggregation, whitebox switching, and where the disaggregated model makes sense in your network.

 

Russ White Guest Pete Lumbis Guest Jeff Tantsura Guest
Jordan Martin Co-Host