IPExpert CoD: MPLS-VPN

This post contains my notes from an old version of IPX Class on Demand by Joe Astorino.

RD has no special meaning—it is only used to make potentially overlapping IPv4 addresses globally unique

Route Targets are additional attributes attached to VPNv4 BGP routes to indicate VPN membership

Export Route Targets identifying VPN membership are appended to customer route when it is converted into VPNv4 route

RD & RT are extended BGP communities; neighbor send-community extended is required!

RR for VPNv4 does not need to be the same as RR of IPv4.

PE imposes 2 labels, the one if from LDP, and the bottom one is from VPNv4 address-family.

Each bgp address-family is a different RIB.

  • Import policy means that routes will come from the VPN extended community
  • Export policy means that routes will go to the VPN extended community

ARF –Automatic Route Filtering:  Only VPN information matching a locally configured RT will be imported
Could be disabled: no default bgproute-target filter

By default, when running OSPF over Frame-Relay and network type is anything except point-to-multipoint, on a spoke, the nexthop for a route originated  from another spoke will be that spoke.
But when the network type is point-to-multipoint, the nexthop will be the hub, and a host route for each spoke will exist.
So make sure to use point-to-multipoint when using MPLS.

RIP/EIGRP address-family version and summarization is different form the RIP/EIGRP’s itself.

When the customer needs the same AS on multiple sites, the AS Override feature should be triggered. So the PE will override its (prepend). Another way to handle this requirement is using allowas-in. Continue reading “IPExpert CoD: MPLS-VPN”

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IPExpert CoD: MPLS & LDP

This post contains my notes from an old version of IPX Class on Demand by Joe Astorino.

# hiding MPLS topology by just incrementing TTL 1 time when reaching the CE
router(config)# no ip mpls propagate-ttl

MPLS MTU is automatically decreased on LAN interfaces and increased on WAN interfaces.

Default mpls mtu is 1512 which supports 3 labels; MPLS MTU can be set by mpls mtu x

LDP router-id should be routable on network.

Connected routes are advertised as implicit-null label for PHP on upstream router

router(config)# mpls ldp neighbor ip labels accept acl
router(config)# mpls ldp tcp pak-priority //Kinda like setting QoS for LDP
!
#Like "ip accounting"
router(config-if)# mpls accounting experimental input/output
router(config-if)# mpls netflow egress
!
router# show mpls ldp binding // LIB
router# show mpls forwarding table // LFIB
router# show ip route // RIB
router# show ip cef ip detail //FIB

To clear LIB:

router(config)# no mpls ip
router(config)# mpls ip

PHP is the default.

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MPLS Building Blocks

IP routers make forwarding decision based on IP packet header, and local CEF and FIB table.
MPLS routers make forwarding decision based on the MPLS label and the LFIB .
MPLS is great technology these days not because it forwards the packets faster , but because of applications and solutions we can provide for our customers like MPLS VPN’s .

MPLS uses the IP routing information to determine the direction and next hop to forward a labeled packet .

Does this before the first packet even arrives.

Continue reading “MPLS Building Blocks”

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Default-route in EIGRP

I know it’s not such tricky thing, but to have in mind…

There are two solutions to originate 0.0.0.0/0 in EIGRP:

  1. (My preferred one) Static 0.0.0.0 0.0.0.0 pointing to an Interface (not next-hop) + network 0.0.0.0
    This way, there is no need of “auto-summary”, so you can use it switched off.
  2. Static 0.0.0.0 0.0.0.0 pointing to next-hop + “auto-summary” + “ip default-network
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Cisco DCI Design & Implementation

Being involved in different Data Center design projects requires you knowing how to interconnect Data Centers. Below you’ll find my notes from Cisco Data Center Design & Implementation Guide, System Release 1.0.

DCI Business DriversHA Clusters/Geoclusters
  • Microsoft MSCS
  • Veritas Cluster Server (Local)
  • Solaris Sun Cluster Enterprise
  • VMware Cluster (Local)
  • VMware VMotion
  • Oracle Real Application Cluster (RAC)
  • IBM HACMP
  • EMS/Legato Automated Availability Manager
  • NetApp Metro Cluster
  • HP Metrocluster
Active/Standby Migration, Move/Consolidate Servers
  • VMware Site Recovery Manager (SRM)
  • Microsoft Server 2008 Layer 3 Clustering
  • VMware Vmotion

The applications above drive the business and operation requirement for extending the Layer 2 domain across geographically dispersed data centers. Extending Layer 2 domains across data centers present challenges including, but not limited to:

  • Spanning tree isolation across data centers
  • Achieving high availability
  • Full utilization of cross sectional bandwidth across the Layer 2 domain
  • Network loop avoidance, given redundant links and devices without spanning tree

Continue reading “Cisco DCI Design & Implementation”

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