About Francois Lieuze

Francois Lieuze · 12-24-2025

Hi community, I have a customer which operates a DC split in two locations, and which uses back-to-back vPC + MST to interconnect those locations. Furthermore, L3 routing is handled by two Catalyst 9400 running HSRP. A network diagram is given belo...

Francois Lieuze · 11-23-2020

Hello guys, I have some questions regarding MTU and the different way to configure it on Cisco devices and I don't find any good documentation on that particular topic. First of all, what will happen if a device receive a packet larger than the MTU o...

Francois Lieuze · 05-19-2020

Hello guys, I have to perform a QoS design which leverage Shaping & CBWFQ and I have a question regarding buffering. Target platforms are ISR4431 & ISR 4451X. I'm quite of struggling to find the way IOS-XE allocate buffers and if the queue-limit fot ...

Francois Lieuze · 09-20-2018

Hello Guys, I'm using MPLS over GRE. The same router (an ISR 4k) is performing label imposition and tunneling. From my understanding, Cisco IOS-XE default behavior for MPLS over GRE encapsulation is the following: Copy IP precedence bits into MPLS EX...

Francois Lieuze · 08-02-2018

Hello, For some too-long-to-explain reasons, I have to deploy a, let’s face it, quite weird architecture. A very simplified diagram is enclosed. To summarize, each site has two WAN accesses. These WAN accesses have to be completely separated, even ...

Francois Lieuze · 01-12-2026

Hi Christian, I thought it was the case, but when I read NX-OS Configuration Config Guide, there is this limitation stating that “Peer-switch can only be configured if both VPC peers share the same priority, and are root for all VLANs or MST instance...

Francois Lieuze · 01-09-2026

Hello Pavel, thank you for the answer and sorry for my belated reaction. I have just another remark: if I enable BPDU Filtering on the inter-DC links, I guess the two vPC pairs will see themselves as MST root, so in that case I should probably keep p...

Francois Lieuze · 12-28-2025

Hello Mark, Ok, poor choice of words on my side... My customer ask me specifically if their spanning-tree design was OK after this outage or if there is something to change. They also wan't to add a new Nexus pair in one of the DC. Let's assume my qu...

Francois Lieuze · 12-22-2025

Hi community, Sorry to "resurrect" this (not-so) old topic, but I have a customer in the exact same situation (back-to-back vPC + MST) and I don’t want to miss something here and the information may be helpful to others. According to NX-OS Configurat...

Francois Lieuze · 08-07-2018

Hello guys, Any idea on that ? Right now, I think I'll go for 6 separated DMVPN (phase 1 only) + static tunnels between my hubs sites. François

Member Since	‎02-21-2012 07:44 AM
Date Last Visited	‎12-25-2025 03:52 AM
Posts	50
Total Helpful Votes Received	16

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Nexus back-to-back vPC design MST

Configuring MTU, yes, but where?

QoS and buffers on ISR4k

DSCP in MPLS over GRE

DMVPN multiple hubs topologies

Re: Nexus back-to-back vPC design MST

Re: Nexus back-to-back vPC design MST

Re: Nexus back-to-back vPC design MST

Re: Nexus back-to-back vPC design with two root ports

Re: DMVPN multiple hubs topologies