Archive

Category Archives for "ipSpace.net"

Fun Times: Is Cisco ACI Dead?

A recent blog post by Andrew Lerner asks whether Cisco ACI is dead. According to Betteridge’s law of headlines, the answer is NO (which is also Andrew’s conclusion), but I liked this gem:

However, Gartner assesses that Nexus Dashboard Fabric Controller is the optimal fabric management software for most Cisco data center environments.

An automation intent-based system provisioning a traditional routed network is considered a better solution than a black-box proprietary software-defined blob of complexity? Who would have thought…

Fun Times: Is Cisco ACI Dead?

A recent blog post by Andrew Lerner asks whether Cisco ACI is dead. According to Betteridge’s law of headlines, the answer is NO (which is also Andrew’s conclusion), but I liked this gem:

However, Gartner assesses that Nexus Dashboard Fabric Controller is the optimal fabric management software for most Cisco data center environments.

An automation intent-based system provisioning a traditional routed network is considered a better solution than a black-box proprietary software-defined blob of complexity? Who would have thought…

From Bits to Application Data

Long long time ago, Daniel Dib started an interesting Twitter discussion with this seemingly simple question:

How does a switch/router know from the bits it has received which layer each bit belongs to? Assume a switch received 01010101, how would it know which bits belong to the data link layer, which to the network layer and so on.

As is often the case, Peter Paluch provided an excellent answer in a Twitter thread, and allowed me to save it for posterity.

From Bits to Application Data

Long long time ago, Daniel Dib started an interesting Twitter discussion with this seemingly simple question:

How does a switch/router know from the bits it has received which layer each bit belongs to? Assume a switch received 01010101, how would it know which bits belong to the data link layer, which to the network layer and so on.

As is often the case, Peter Paluch provided an excellent answer in a Twitter thread, and allowed me to save it for posterity.

How Routers Became Bridges

Network terminology was easy in the 1980s: bridges forwarded frames between Ethernet segments based on MAC addresses, and routers forwarded network layer packets between network segments. That nirvana couldn’t last long; eventually, a big-enough customer told Cisco: “I don’t want to buy another box if I already have your too-expensive router. I want your router to be a bridge.

Turning a router into a bridge is easier than going the other way round1: add MAC table and dynamic MAC learning, and spend an evening implementing STP.

How Routers Became Bridges

Network terminology was easy in the 1980s: bridges forwarded frames between Ethernet segments based on MAC addresses, and routers forwarded network layer packets between network segments. That nirvana couldn’t last long; eventually, a big-enough customer told Cisco: “I don’t want to buy another box if I already have your too-expensive router. I want your router to be a bridge.

Turning a router into a bridge is easier than going the other way round1: add MAC table and dynamic MAC learning, and spend an evening implementing STP.

netlab Release 1.3: VXLAN and EVPN

netlab release 1.3 contains two major additions:

  • VXLAN transport using static ingress replication or EVPN control plane – implemented on Arista EOS, Cisco Nexus OS, Dell OS10, Nokia SR Linux and VyOS.
  • EVPN control plane supporting VXLAN transport, VLAN bridging, VLAN-aware bundles, and symmetric IRB – implemented on Arista EOS, Dell OS10, Nokia SR Linux, Nokia SR OS (control plane), VyOS, and FRR (control plane).

Here are some of the other goodies included in this release:

netlab Release 1.3: VXLAN and EVPN

netlab release 1.3 contains two major additions:

  • VXLAN transport using static ingress replication or EVPN control plane – implemented on Arista EOS, Cisco Nexus OS, Dell OS10, Nokia SR Linux and VyOS.
  • EVPN control plane supporting VXLAN transport, VLAN bridging, VLAN-aware bundles, and symmetric IRB – implemented on Arista EOS, Dell OS10, Nokia SR Linux, Nokia SR OS (control plane), VyOS, and FRR (control plane).

Here are some of the other goodies included in this release:

Feedback Appreciated: Next-Generation Metro Area Networks

Etienne-Victor Depasquale, a researcher at University of Malta, is trying to figure out what technologies service providers use to build real-life metro-area networks, and what services they offer on top of that infrastructure.

If you happen to be involved with a metro area network, he’d love to hear from you – please fill in this survey – and he promised that he’ll share the results of the survey with the participants.

Feedback Appreciated: Next-Generation Metro Area Networks

Etienne-Victor Depasquale, a researcher at University of Malta, is trying to figure out what technologies service providers use to build real-life metro-area networks, and what services they offer on top of that infrastructure.

If you happen to be involved with a metro area network, he’d love to hear from you – please fill in this survey – and he promised that he’ll share the results of the survey with the participants.

1 52 53 54 55 56 180