#lagging frr

[ffsg0jo]

Moots and who you think their secret admirer would be?

i have so many moots, but i think ill mention the ones i interact with more often, if any moots want me to add them please feel free to send me an ask and ill respond with one !!

@arquitecturadelanada + gojo satoru -- ive already verbal diarrhoead about this but him and his actions are constantly teetering on the edge of ‘just friends’ and ‘more than friends’. you usually play it off as gojo being gojo, but sometimes it all just feels so real but then he, in typical gojo fashion, does something that makes you believe otherwise

@animated-moon + kageyama tobio -- he’d admire your hard work and skill. it’s something he finds very attractive and he just cant but develop a mini crush on you. you’re also constantly making him laugh and smile and what’s there not to love about you?

@akirine + mikasa ackerman -- mikasa doesn't know if you are just a really good friend or if she has a crush on you. she’s puzzled about her own feelings but as long as she gets to hang out with you and be with you she’d keep her feelings hidden

@avid-idiot + miya osamu -- ik you’re in love with his brother, but i feel like osamu cant help but fall in love with you too. you’re sweet and nurturing and you're just the loveliest person he’s ever met. he’d never do anything to jeopardise your relationship with atsumu, but he shows you his love through cooking for you and only you, and even sharing his food with you 

@beelzebubaz + me tsukishima kei -- his cheeks turn pink whenever you smile at him with that gorgeous smile of yours. he knows you’re spoken for but he really can’t help admire you from afar. and he’d be damned if anyone finds out about his crush, he’s taking that to the grave with him

@cupidines + sukuna -- sukuna doesn't know why but he has a sudden urge to protect you and keep you away from harm at all costs. whenever he sees you fighting alongside yuuji his heart seems to beat faster and faster and he’s sitting on the edge of his throne without even realising. he’d even intervene and take control of yuuji if it meant to save you

@dani-shitting-around + sugawara koushi -- please you’re just so fun and so bubbly, he can’t help but admire you. he thinks you’re radiance rivals the sun and just loved being in your company. suga’s a very good friend and senpai though, so he keeps his feelings to himself and even gives you relationship advice when you need it

@gumiresque + choso -- the only type of love choso has ever felt almost as strong as the love he has for you, is for his brothers. but he just feels so so differently about you. his hearts starts beating so much faster, his breath quickens, and he just feel so nervous around you. he wants to give you the world on a gold platter and make you happy  

@httptouya + kirishima eijirou -- he's just so smitten by you because of how kind you are and he's lowkey envious of your s/o. he's respectful in a sense that he would never outright try to ruin your relationship but he does subtle things that makes your heart flutter for him sometimes

@iwaso + sakusa kiyoomi -- i feel like he just vibes with you. he's not a secret admirer in a lover way, but more like oh he's cool and id love to hang out with them

@loving-august + eren yeager -- idk i just feel like you and eren would be good together and belong together. but because of all the edgy angst he's going through he'd push you aside and distance himself from you. he doesn't want you getting hurt and doesn't want anything bad happening to you, and make sure to keep tabs on you and your safety

@memosa + ushijima wakatoshi -- this fool is not a secret admirer. he straight up tells you how much he likes and admires you, literally screams it out loud on the rooftops. he's sweet and he's just the best, but its definitely no secret he's in love with you lmaoo

@mel-core + bakugo katsuki -- you two are literally canon at this point, idek what to say. it would start off as katsuki secretly admiring you, mainly because he doesn't know how to process or express his feelings for you. but you catch on and you let katsuki know that he's worth loving and loved, by you

@okkatsudon + levi ackerman -- he'd be so lowkey about it and most people wouldn't even realise that he's soft on you, except those that know levi well. erwin notices in the way he scans the crowd for you after a mission only relaxes when he find you and hange sees it in the way his eyes soften soften looking at you

@rinphoria + sero hanta -- he doesn't try to hide it to be fair, he doesn't really want to. he'd tease you and jokingly flirt with you and you both play it off as a joke. the only hint that it could be something more is the faint blush coating his cheeks

@towoshi + kuroo tetsurou -- he realised that he loved you a little too late, but he's loved you ever since. he's really good at hiding his feelings though so most of what he does can be passed off as kuroo just being a really good supportive friend. it's his biggest and only regret, not confessing sooner

@sunat2508 + jean kirstchein -- we've had a million conversations about this and i am dead fixed on this fr

@silkylious + megumi fushiguro -- he knows that your heart belongs to gojo and he knows that you won't ever see him that way but the heart wants what it wants and he can't help himself. he totally respects both you and gojo so he'd never try anything but he'd make sure that you're constantly okay and safe and look after you when gojo isn't around

@tsukina + suna rintaro -- hear me out bestie, it could be like rivals to friends to lovers, but unrequited. he slowly starts falling in love with you and the back and forth teasing dynamic that you two have, but he knows he can't have you. it crushes his heart but as long as he still gets to be with you, as friends he's okay. as long as you're happy, he's happy

@thegojosimpehe + bokuto koutarou -- he does not understand the art of subtlety, and that's okay because we love bo in this household. everyone can and their grandma's know that bo has a soft spot for you and its only a matter of time until you find out

#🌻.feelingsunny #🌻.nonny<33 #im sorry this took so so long #my brain is not working i stg #lagging frr

[stephenlibbyy]

EVPN-PIM: Anycast VTEPs

This is the second of the two part EVPN-PIM blog series exploring the feature and network deployment choices. If you missed part one, learn about BUM optimization using PIM-SM here.

Anycast VTEPs

Servers in a data-center Clos are typically dual connected to a pair of Top-of-Rack switches for redundancy purposes. These TOR switches are setup as a MLAG (Multichassis Link Aggregation) pair i.e. the server sees them as a single switch with two or more bonded links. Really there are two distinct switches with an ISL/peerlink between them syncing databases and pretending to be one.

The MLAG switches (L11, L12 in the sample setup) use a single VTEP IP address i.e. appear as an anycast-VTEP or virtual-VTEP.

Additional procedures involved in EVPN-PIM with anycast VTEPs are discussed in this blog.

EVPN-PIM in a MLAG setup vs. PIM-MLAG

Friend: “So you are working on PIM-MLAG?” Me: “No, I am implementing EVPN-PIM in a MLAG setup” Friend: “Yup, same difference” Me: “No, it is not!” Friend: “OK, OK, so you are implementing PIM-EVPN with MLAG?” Me: “Yes!” Friend: “i.e. PIM-MLAG?” Me: “Well, now that you put it like that….……..NO, I AM NOT!!”

Yes, that conversation actually happened! My frustration may seem funny but this feature’s naming has caused a fair amount of confusion. And the fact that EVPN-PIM borrows some design elements from PIM-MLAG only adds to that confusion.

PIM-MLAG deals with PIM in the overlay. PIM-EVPN on the other hand serves a very simple/specific purpose of optimizing overlay-BUM in the underlay using PIM-SM i.e. it only deals with PIM in the underlay network.

Chanting “overlay, underlay, overlay, underlay, overlay, underlay….” helps clarify that. Ok, maybe it doesn’t but hopefully this blog will!

Multicast tunnel origination

Source registration

L1X (L11,L12) is responsible for encapsulating overlay BUM in rack-1 with a multicast VxLAN header and sending it down the underlay-MDT. The MDT first needs to setup and to do that both L11 and L12 individually null-register the same SG i.e. (36.0.0.11, 239.1.1.100) with the RP. SP1/SP2 learn the SG via these PIM null-registers (and MSDP) and trigger the SPT setup towards 36.0.0.11.

SP1/SP2 see the MLAG switches L11 and L12 as two separate multicast routers i.e. an ECMP to 36.0.0.11 and can choose either switch as the upstream RPF neighbor. In the sample topology only SPI has the OIL needed to initiate the SPT. It runs the control-plane ECMP hash on (36.0.0.11, 239.1.1.100) and choses L11 as the upstream RPF neighbor.

The dual connected server (H11) on the other hand sees the MLAG switches L11 and L12 as a single switch and LAG hashes the BUM traffic to either L11 or L12. If the traffic is received by L11 the traffic flow is apparent. L11 encapsulates the BUM packet with the multicast vxlan header (SIP=36.0.0.11, DIP=239.1.1.100) and sends it to SP1. But what if H11 sends the packet L12? L12 cannot send the multicast-vxlan-encapsulated traffic to SP1. For one it doesn’t have the mroute-OIL to do that and even if it decided to play games and send it to SP1 the multicast traffic is simply dropped on SP1 because of RPF check failures i.e. SP1 only accepts flow (36.0.0.11, 239.1.1.100) from swp1 i.e L11. So now what?

Note: It is also possible that both spine switches are interested in joining the SPT and they can choose differently i.e. SP1 can join L11, SP2 can join L12. All of these combinations are addressed in this design.

Traffic flow

The downstream multicast router picks the RPF neighbor and the MLAG pair doesn’t have a way to influence the decision. To accommodate that the overlay BUM flow is encapsulated and sent to the MLAG peer which subsequently “multicast routes” the already encapsulated flow based on its local OIL.

FRR/pimd adds the peerlink-sub-interface as an OIF (internally) to every origination-mroute (S=local-VTEP-IP, G=BUM-mcast-IP).

L11

L12

Now if H11 sends a BUM packet to L12 (flow-B in the figure) it is multicast-vxlan-encapsulated and sent over the peerlink-sub-interface (peerlink-3.4094) to L11. L11 treats that as underlay multicast traffic simply multicast-routing it of its own local OIL (swp3).

A couple of items of note

To prevent RPF check failures the IIF of the origination mroutes is statically (internally) pinned to the peerlink-sub-interface.

The dataplane explicitly removes the IIF from the OIL before forwarding IP multicast packets; this allows the peerlink-sub-interface to be present in the IIF and the OIL.

Multicast tunnel termination

MDT setup

Both MLAG switches join the MDT (RPT) and pull down traffic for each BUM multicast group. This is done to allow fast failover if one of the MAG switches were to go down.

To prevent duplicates to the dual-connected receiver only one MLAG switch, the DF (Designated Forwarder) terminates the multicast VxLAN tunnel. DF election is run, between the two MLAG switches, on per-BUM-mcast group basis.

DF election for decapsulation

The MLAG switch with the lowest cost to the RP wins the election for the multicast group. If both switches have an equal RPF cost the MLAG role is used a tie-breaker. And the MLAG primary wins.

The winner (DF) includes the termination-device ipmr-lo in the OIL of all the termination-mroutes

The non-DF doesn’t

In the sample topology L11 (the DF winner) terminates the multicast VxLAN tunnels and subsequently bridges the BUM overlay packets to local servers H11 and H12. L12 doesn’t terminate the multicast VxLAN tunnel.

peerlink-dualink-filter: Traffic received from the peerlink is never forwarded out of a duallink; this includes both access-dualinks and network-duallinks. So decapsulated traffic received by L12 from L11 over the peerlink is never sent back over the VxLAN overlay network.

Configuration

The MLAG switches (L11 and L12) functioning as an anycast VTEP are configured identically for EVPN-PIM i.e.

Enable PIM on the uplinks and lo.

Configure static RP.

Enable PIM on the peerlink-sub-interface; this is the only additionally configuration need on anycast VTEPs (vs. single VTEPs).

Summary

That’s EVPN-PIM with anycast-VTEPs. Again, if you missed out on the first blog of this series, check out the that blog here. If you have questions or need further help with the config choices just ask us.

I’m also open to writing about other topics so if  you liked this series and  want me to write about anything else, leave a comment below and I’ll see what I can do.

EVPN-PIM: Anycast VTEPs published first on https://wdmsh.tumblr.com/