Al CisCon 2017, Ruben del Monte (Network Consulting Engineer in IT Global Consulting Srl, CCIE #54221) ha tenuto uno speech dal titolo "I problemi di scalabilità delle tradizionali reti IP nei moderni datacenters". Abstract presente su http://www.ciscon.net/il-programma/

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CisCon2017
I problemi di scalabilita’ delle
tradizionali reti IP nei moderni
datacenters
relatore: Ruben Del Monte

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• Ruben Del Monte, CCIE #54221
• Network Consulting Engineer c/o IT Global
Consulting
• Cisco Red Badge
• Technical lead c/o Vodafone Group Datacenter,
“Stabilization” programme

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Cosa si intende per “scalare” (to scale)
dal punto di vista delle infrastrutture IP
• Aggiungere risorse in maniera organica e
funzionale ad un’infrastruttura, in modo da
aumentarne la capacita’ – erogazione di risorse
• Replicare un certo numero di volte un dato
elemento all’interno di un particolare contesto o
configurazione, in modo da aumentare la
funzionalita’ globale del contesto stesso –
fruizione di risorse

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Design IP tradizionale – standard corporate networks
QFP QFP
L3 – ROUTED
DOMAIN
L2 – SWITCHED
DOMAIN
CORE LAYER
DISTRIBUTION
LAYER
ACCESS LAYER
POD 1 POD 2 POD 3
FHRP GROUP A FHRP GROUP B FHRP GROUP C
VLAN 100-150 VLAN 151-201 VLAN 202-252

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Design IP tradizionale – adattato al Datacenter (scale out)
QFP QFP
L3 – ROUTED
DOMAIN
L2 – SWITCHED
DOMAIN
CORE LAYER
DISTRIBUTION
LAYER
ACCESS LAYER
POD 1
FHRP GROUP A FHRP GROUP B
VLAN 100-150 VLAN 151-201

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STP operations: bridge priority and port role election
POD 2
D-BDG1
ROOT
D-BDG2
D-BDG3 D-BDG4 D-BDG5 D-BDG6
L3 – ROUTED
DOMAIN
L2 – SWITCHED
DOMAIN
D D D
D
D R
R R R RAltn Altn Altn Altn
Altn
Altn
Altn
Altn

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STP operations: available paths (stable topology)
POD 2
D-BDG1
ROOT
D-BDG2
D-BDG3 D-BDG4 D-BDG5 D-BDG6
L3 – ROUTED
DOMAIN
L2 – SWITCHED
DOMAIN
D D D
D
D R
R R R R

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Le tecnologie ed il design IP tradizionali non scalano
all’interno di una LAN di grosse dimensioni
• Ethernet: tecnologia broadcast multi-access (any-to-any stateless
transport)
• Si adatta male a situazioni di asimmetria
• Dipende da Spanning Tree per prevenire loops data-link
• Spanning-tree comporta alcune (forti) limitazioni:
• Diametro massimo 20 bridge
• Deve convergere/ri-convergere
• Dicotomie tra versioni diverse del protocollo
• Un solo forwarding path
• Complesso da mantenere, prono ad errori in topologie complesse
• Alta affidabilita’ in L3 gateway vincolata ad FHRP (HSRP, GLBP,
VRRP)
• Max. 4 gateways (act/stby o act/act)
• Accentua asimmetrie, amplificando gli effetti di unicast flooding
• Failover basato su timers

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VPC
• Supportato da Nexus 3K, 5K, 6K , 7K, 9K
• E’ necessaria solo la Base License
• Multi-chassis Etherchannel su Cisco Nexus
• Virtualizza il forwarding plane di due peers
• Nella topologia L2 aggrega i due peers
• I due peers mantengono control plane separati
• Scale-UP, piu’ banda disponibile e resilienza
• Evita single point of failure

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VPC – peerings and link roles
POD 55
L3 – ROUTED
DOMAIN
L2 – SWITCHED
DOMAIN VPC PL
VPC PKA
VPC PKA
VPC PL
ROUTED INTERLINK
INTERNAL
ROUTING
DOMAIN
ROUTED LINK ROUTED LINK
VPC
VPC
DISTRIBUTION
SWITCHES – VPC PEERS
ACCESS SWITCHES –
VPC PEERS

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VPC – logical topology (STP/HSRP perspective)
POD 55
L3 – ROUTED
DOMAIN
L2 – SWITCHED
DOMAIN D-BDG1/D-BDG2
STP ROOT, PEER-
SWITCH ENABLED
D
R D-BDG3/D-BDG4
STP DESIGNATED,
PEER-SWITCH
ENABLED
D-BDG1 HSRP
ACTIVE
D-BDG2 HSRP
ACTIVE

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FabricPath
• Supportato da 5K, 6K, 7K (F linecards)
• Necessaria ENHANCED LAYER 2 LICENSE
• TRILL, implementazione Cisco proprietaria
• MAC-in-MAC routing, preserva tag 802.1q
• Cambia il design da 3-tier a CLOS fabric
• Scale-OUT fino 768 nodi (rif. N7K SUP2-E)
• Migliora il comportamento generale del data
plane

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FabricPath = MAC-in-MAC routing

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FabricPath – CLOS fabric
POD 1
FABRICPATH
DOMAIN
CLASSICAL
ETHERNET
DOMAIN
SPINE
SWITCHES
LEAF SWITCHES
SWID 1 SWID 2
SWID 11 SWID 12 SWID 21 SWID 22 SWID 31 SWID 32
ESWID 111 ESWID 211 ESWID 311
STP ROOT
BRIDGE
STP ROOT
BRIDGE
STP ROOT
BRIDGE

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FabricPath – multi-destination tree
POD 1
FABRICPATH
DOMAIN
CLASSICAL
ETHERNET
DOMAIN
SPINE
SWITCHES
LEAF SWITCHES
SWID 1 SWID 2
SWID 11 SWID 12 SWID 21 SWID 22 SWID 31 SWID 32
ESWID 111 ESWID 211 ESWID 311
STP ROOT
BRIDGE
STP ROOT
BRIDGE
STP ROOT
BRIDGE
MDT1
ROOT
MDT2
ROOT

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FabricPath – internal/external routing
POD 2
FABRICPATH
DOMAIN
CLASSICAL
ETHERNET
DOMAIN
SPINE
SWITCHES
LEAF
SWITCHES
SUPER-
SPINE
SWITCHES
POD-X
EXTERNAL
ROUTING
DOMAIN
QFP QFP
SPINE1 ANYCAST
HSRP ACTIVE
SPINE2 ANYCAST
HSRP ACTIVE
SPINE3 ANYCAST
HSRP ACTIVE
SPINE4 ANYCAST
HSRP ACTIVE
ANYCAST HSRP
SWID

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Virtual Extensible LAN
• Supportato da 3K (non tutte le serie), 5K, 6K, 7K, 9K
• Necessaria Enterprise Service License
• RFC 7348
• Virtualizza il data plane (overlay); incapsula trama ethernet
in VXLAN header (UDP), senza preservare tag 802.1q
• Design di riferimento per underlay network:
• CLOS all’interno della stessa fabric
• Indipendente in DCI o nel trasporto verso l’esterno
• Scala fino a 128 VTEP nella stessa fabric (rif. N7K SUP2-E)
• Consente inter-cloud on-premise oppure hybrid cloud =
trasporto L2 diretto da DC a DC
• Any-to-any stateless transport (Ethernet-wise)

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Virtual Extensible LAN – EoVXLAN(oUDP)= OVERLAY

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Virtual Extensible LAN – Flood-and-learn
POD 1
VXLAN DOMAIN
CLASSICAL
ETHERNET
DOMAIN
SPINE
SWITCHES
LEAF SWITCHES
Lo0 1.1.1.1/32 Lo0 1.1.1.2/32
Lo0 1.1.1.3/32
secondary –
VTEP SOURCE
Lo0 2.2.2.1/32 Lo0 2.2.2.2/32
Lo0 2.2.2.3/32
secondary –
VTEP SOURCE
Lo0 3.3.3.1/32
NVE 1 NVE 2 NVE 3
OSPF AREA
0.0.0.1
IP PIM SPARSE-
MODE
L3 GATEWAY:
INTER-VNI
ROUTING,
EXTERNAL
ROUTING
DOMAIN
Lo0 3.3.3.2/32
Lo0 3.3.3.3/32
secondary –
VTEP SOURCE
QFP QFP
PIM SM
ANYCAST RP
PIM SM
ANYCAST RP

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Virtual Extensible LAN – Flood-and-learn – L3 routing option 1 – external L3 GW
POD 1
VXLAN DOMAIN
CLASSICAL
ETHERNET
DOMAIN
SPINE
SWITCHES
LEAF SWITCHES
NVE 1 NVE 2 NVE 3
QFP QFP
VLAN 100
10.1.100.0/24
VNID
100100
Po1.100 HSRP ACTIVE
Po1.200 HSRP STBY
Po1.100 HSRP STDBY
Po1.200 HSRP ACTIVE
VNID
100100
100200
VLAN 200
10.1.200.0/24
VNID
100200

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Virtual Extensible LAN – Flood-and-learn – L3 routing option 2 – FHRPoVXLAN – NK9
POD 1
VXLAN DOMAIN
CLASSICAL
ETHERNET
DOMAIN
LEAF SWITCHES
NVE 1 NVE 2 NVE 3
VLAN 100
10.1.100.0/24
VNID
100100
VLAN 100 HSRP ACTIVE
VLAN 200 HSRP STBY
VLAN 100 HSRP STDBY
VLAN 200 HSRP ACTIVE
VLAN 200
10.1.200.0/24
VNID
100200
VXLAN DOMAIN
CLASSICAL
ETHERNET
DOMAIN
SPINE
SWITCHES
L3 GATEWAY:
INTER-VNI
ROUTING,
EXTERNAL
ROUTING
DOMAIN

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Virtual Extensible LAN – Flood-and-learn – OVERLAY
POD 1
VXLAN DOMAIN
CLASSICAL
ETHERNET
DOMAIN
SPINE
SWITCHES
LEAF SWITCHES
NVE 1 NVE 2 NVE 3
VLAN 200
10.1.200.0/24
VLAN 100
10.1.100.0/24
VNID
100100
Po1.100 HSRP ACTIVE
Po1.200 HSRP STBY
Po1.100 HSRP STDBY
Po1.200 HSRP ACTIVE
VNID
100100
100200
VNID
100200
QFP QFP

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Virtual Extensible LAN – MP-BGP L2VPN EVPN = PROGRAMMABLE FABRIC
POD 1
VXLAN DOMAIN
CLASSICAL
ETHERNET
DOMAIN
SPINE
SWITCHES
LEAF SWITCHES
Lo0 1.1.1.1/32 Lo0 1.1.1.2/32
Lo0 1.1.1.3/32
secondary –
VTEP SOURCE
Lo0 2.2.2.1/32 Lo0 2.2.2.2/32
Lo0 2.2.2.3/32
secondary –
VTEP SOURCENVE 1 NVE 2 NVE 3
OSPF AREA
0.0.0.1
IP PIM SPARSE-
MODE
EXTERNAL
ROUTING
DOMAIN
BGP RR
AFI L2VPN EVPN
BGP RR
AFI L2VPN EVPN
BGP RR CLIENT
AFI L2VPN EVPN
AFI IPV4/IPV6 UNICAST
VRF-AWARE (TENANT)
ANYCAST GATEWAY
ROUTE
SUMMARIZATION
BOUNDARY
Lo0 3.3.3.3/32 secondary –
VTEP SOURCE
Lo0 3.3.3.1/32 Lo0 3.3.3.2/32
L3 routed link
QFP QFP
PIM SM
ANYCAST RP
PIM SM
ANYCAST RP

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Virtual Extensible LAN – MPBGP L2VPN EVPN: from multipod to hybrid cloud
POD
11
DCI
QFP QFP
POD
22
QFP QFP
WAN
THIRD-PARTY
CLOUD
SITE 1 – AS
64513
SITE 2 – AS
64513
DCI
MPLS
IBGP-L2VP-EVPN
SERVICE PROVIDER
QFP
QFP
QFP
QFP
QFPQFP
NEXUS 7.7K
VPC
LAYER3 PEER-ROUTER
PEER-GATEWAY
BGP-FREE
NEXUS 7.7K
VPC
LAYER3 PEER-ROUTER
PEER-GATEWAY
BGP-FREE
OSPF AREA 0.0.0.2
IP PIM SPARSE-MODE
BGP RR
AFI L2VPN EVPN
BGP RR CLIENT
AFI L2VPN EVPN
AFI IPV4/IPV6 UNICAST
VRF-AWARE (TENANT)
ANYCAST GATEWAY
OSPF AREA 0.0.0.1
IP PIM SPARSE-MODE
BGP RR CLIENT
AFI L2VPN EVPN
AFI IPV4/IPV6 UNICAST
VRF-AWARE (TENANT)
ANYCAST GATEWAY
BGP RR
/ RR CLIENT
AFI L2VPN EVPN
BGP RR
AFI L2VPN EVPN
BGP RR CLIENT
AFI L2VPN EVPN
BGP RR CLIENT
AFI L2VPN EVPN
BGP RR
/ RR CLIENT
AFI L2VPN EVPN
CRS1000V
VIRTUALIZED
ENVIRONMENT
EBGP-L2VPN-EVPN
PIM SM ANYCAST RP
MSDP
PIM SM ANYCAST RP
MSDP
MSDP
MSDP

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Virtual Extensible LAN – MPBGP L2VPN EVPN: OVERLAY
POD
11
DCI
QFP QFP
POD
22
QFP QFP
WAN
THIRD-PARTY
CLOUD
SITE 1 – AS
64513
SITE 2 – AS
64513
DCI
VPLS
IBGP-L2VP-EVPN
SERVICE PROVIDER
QFP
QFP
QFP
QFP
QFPQFP
NEXUS 7.7K
VPC
LAYER3 PEER-ROUTER
PEER-GATEWAY
BGP-FREE
NEXUS 7.7K
VPC
LAYER3 PEER-ROUTER
PEER-GATEWAY
BGP-FREE
OSPF AREA 0.0.0.2
IP PIM SPARSE-MODE
BGP RR
AFI L2VPN EVPN
BGP RR CLIENT
AFI L2VPN EVPN
AFI IPV4/IPV6 UNICAST
VRF-AWARE (TENANT)
ANYCAST GATEWAY
OSPF AREA 0.0.0.1
IP PIM SPARSE-MODE
BGP RR CLIENT
AFI L2VPN EVPN
AFI IPV4/IPV6 UNICAST
VRF-AWARE (TENANT)
ANYCAST GATEWAY
BGP RR
/ RR CLIENT
AFI L2VPN EVPN
BGP RR
AFI L2VPN EVPN
BGP RR CLIENT
AFI L2VPN EVPN
BGP RR CLIENT
AFI L2VPN EVPN
BGP RR
/ RR CLIENT
AFI L2VPN EVPN
CRS1000V
VIRTUALIZED
ENVIRONMENT
EBGP-L2VPN-EVPN
PIM SM ANYCAST RP
MSDP
PIM SM ANYCAST RP
MSDP
MSDP
MSDPVLAN 50
VNID 100050

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Grazie per l’attenzione