Transcript Master

Técnicas de Alta Disponibilidade para NAPs
Marcelo Molinari – Foundry Networks do Brasil
[email protected]
© 2002 Foundry Networks, Inc.
Agenda
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LINX topology overview
AMS-IX topology overview
Metro Ring Protocol
Virtual Switching Redundancy Protocol
©2002 Foundry Networks, Inc.
London Internet Exchange (LINX)
© 2002 Foundry Networks, Inc.
LINX Topology
©2002 Foundry Networks, Inc.
LINX Topology
• The LINX Network consists of two separate high-
performance Ethernet switching platforms installed
across seven locations.
•
Switches from two equipment vendors are deployed in
two separate networks to provide an extra level of
fault-tolerance, the logic being that both systems
shouldn't develop the same fault at the same time.
©2002 Foundry Networks, Inc.
LINX Topology
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Two switches are installed in every LINX location, and the locations
are interconnected by multiple 10 gigabit Ethernet circuits to form
two physically separate backbone rings.
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Most LINX members connect to both switching platforms, which
reduces the impact of any downtime on a single network element.
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Management of the logical redundancy of the network is done using
MRP (Metro Ring Protocol). In the event of the loss of a network
segment, MRP activates a redundant link within tenths of a second
and restore connectivity.
©2002 Foundry Networks, Inc.
LINX Aggregated Traffic Statistics
©2002 Foundry Networks, Inc.
Amsterdam Exchange (AMS-IX)
© 2002 Foundry Networks, Inc.
AMS-IX Topology
©2002 Foundry Networks, Inc.
AMS-IX Topology
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AMS-IX is a distributed exchange, currently present at five
independent co-location facilities in Amsterdam.
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The AMS-IX topology is built around two hub/spoke arrangements.
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Members with a 10GbE port are connected to Glimmerglass Networks
photonic cross-connects. These L1 switches connect the member
10GbE ports to BigIron RX-16 or NetIron MLX-16 switches.
The core switches are Foundry Networks NetIron MLX-32 switches.
Members connected with GigE, 100Base-TX or 10Base-T ports are
connected to Foundry Networks BigIron 15000 and BigIron RX-8
switches.
©2002 Foundry Networks, Inc.
AMS-IX Topology
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The two core switches run VSRP (Virtual Switch Redundancy
Protocol) to define the active hub/spoke and to automatically fail
over to the other, based on pre-defined triggers (e.g. link failure).
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All edge switches from Foundry follow VSRP automatically. The
Glimmerglass switches follow the VSRP failover based on software
developed at AMS-IX.
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Members can connect to the AMS-IX infrastructure at any of the
five AMS-IX co-locations, at 100 Mbit/s, 1 Gbit/s or 10 Gbit/s.
©2002 Foundry Networks, Inc.
AMS-IX Traffic Statistics
©2002 Foundry Networks, Inc.
Metro Ring Protocol
© 2002 Foundry Networks, Inc.
Metro Ring Protocol (MRP)
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Metro Ring Protocol is a Layer 2 protocol designed to provide
SONET-like, high speed, fault tolerant, fast recovery for Metro
Ethernet networks.
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MRP SONET-like features provide:
– Sub-second failover
– Efficient use of bandwidth with topology groups (802.1s based)
– Scalable protection for multiple VLANs
– Large Scale L2 MANs with multi-ring support
– Highly flexible network designs
– Works with other L2 features
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Runs on all Ethernet and PoS/SDH interfaces, including 10 Gigabit
©2002 Foundry Networks, Inc.
How it works
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A single node is defined as the Ring
Master Node
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All other nodes are defined as Ring
Member Nodes
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The Master Node prevents loops by
blocking its secondary port
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Ring Hello Packets are generated
by the Master Node to check ring
integrity
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As long as the master sees its own
Hello packets on the secondary
port, ring health is verified, and
secondary port remains blocked
Primary
(Forwarding)
Secondary
(Blocking)
©2002 Foundry Networks, Inc.
Rapid Failover
NetIron 400
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Hello packets are hardware forwarded by
the nodes in the ring to ensure fastest
failure detection.
NetIron 400
Master considers ring broken if no Hello
packets are received within 300 ms (3
consecutive Hellos are lost).
By changing timers and using messages
sent by the node where the ring broke, it
is possible to achieve recovery times from
150 ms to 200 ms.
NetIron 400
NetIron 400
If no Hellos are received, Master
transitions secondary port into forwarding
state to restore ring connectivity.
To provide reliable flushing of stale MAC
entries, Master sends 3 consecutive TCN
notifications.
FAULT
NetIron 400
NetIron 400
NetIron 400
NetIron 400
©2002 Foundry Networks, Inc.
Link Restoration
Link restored
Preventing Temporary Loops
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When an MRP port goes up, it goes into
pre-forwarding mode to avoid the
creation of temporary loops.
NetIron 400
PF
PF
NetIron 400
NetIron 400
In pre-forwarding mode the port
forwards no data, but only the ring hello
packets from the master.
NetIron 400
Master sees its own RHP, detects that
ring integrity has been restored, puts its
secondary port in blocking mode.
From that point onwards, master sends
RHPs with the Forwarding flag bit set,
indicating that members should
transition their ports from preforwarding to forwarding.
The Forwarding flag bit is always set, as
long as the master is blocking its
secondary port.
NetIron 400
F
F
NetIron 400
NetIron 400
NetIron 400
©2002 Foundry Networks, Inc.
Topology Groups
Topology Group
Master VLAN
A VLAN running a control protocol (or more) that controls the
active topology for the whole topology group. Control
protocols: STP, RSTP, MRP, VSRP.
Member VLAN
A VLAN running NO control protocol of its own but rather
follows the active topology of the master VLAN..
Member VLAN Group
A group of VLANs running NO control protocol of their own
but rather follow the active topology of the master VLAN.
VLAN groups are defined via the “vlan-group” command.
©2002 Foundry Networks, Inc.
Efficient use of Ring Bandwidth
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MRP Supports Multiple Topology groups within a Ring
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Each Topology group contains a Master VLAN and Member VLANs
An MRP Node can be both a Master node and Member Node for different
topology groups
Master VLANs generate Hello packets and block secondary ports
4094 VLANs can be divided among up to 255 Topology groups
Topo
Group 1
Topo
Group 2
©2002 Foundry Networks, Inc.
Using Multiple Rings
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There are 3 ring scenarios:
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Single ring
Rings that don’t overlap
Overlapping rings that share links
Each Ring runs its own instance of MRP
A ring node can be Master for Multiple rings
BigIron 4000
BigIron 4000
BigIron 4000
BigIron 4000
BigIron 4000
BigIron 4000
BigIron 4000
BigIron 4000
BigIron 4000
BigIron 4000
BigIron 4000
BigIron 4000
BigIron 4000
BigIron 4000
BigIron 4000
Single Ring
BigIron 4000
BigIron 4000
Non-Overlapping Ring
BigIron 4000
BigIron 4000
Overlapping Rings
Phase II
Phase I
©2002 Foundry Networks, Inc.
Example Scenarios – Phase I
– High-speed 10 GE trunks for Metro
rings or IXPs
– Provides sub-second fault-detection
and fail-over
– Superior scalability: no limit on
maximum number of nodes per ring
– Counter rotating topology groups
provide efficient use of bandwidth
BigIron 4000
BigIron 4000
BigIron 8000
S6
Secondary
Ring
2
port
BigIron 4000
S1
Master
node
Primary
BigIron 4000
port
S5
Ring
1
BigIron 8000
S2
BigIron 4000
BigIron 4000
S5
BigIron 4000
Ring
3
S4
BigIron 4000
S4
S3
BigIron 4000
Ring
4
BigIron 4000
Master
node
BigIron 4000
©2002 Foundry Networks, Inc.
Example Scenarios – Phase II
– Shared ring support
– Increased reliability
– Increased bandwidth
BigIron 4000
BigIron 4000
BigIron 8000
S6
Secondary
Ring
2
port
BigIron 4000
S1
Master
node
Primary
BigIron 4000
Master
node
S5
BigIron 4000
port
Ring
1
BigIron 8000
S2
BigIron 4000
BigIron 4000
S5
BigIron 4000
Ring
3
S4
BigIron 4000
S4
S3
BigIron 4000
Ring
4
BigIron 4000
Master
node
BigIron 4000
©2002 Foundry Networks, Inc.
Interface Flexibility
• Support for Mixed interfaces
- 10Gig & Gig
- Gig & 10/100
- 10Gig & PoS/SDH
• Support for Trunked interfaces
- 10Gig & Gig
- PoS/SDH
Slower link
BigIron 8000
S6
BigIron 8000
S6
Secondary
Secondary
port
port
BigIron 4000
S1
Primary
BigIron 4000
S1
Primary
port
S5
BigIron 8000
BigIron 8000
S2
BigIron 4000
Master
node
BigIron 4000
BigIron 4000
port
S5
Master
node
S2
BigIron 4000
S4
S4
BigIron 4000
BigIron 4000
S3
S3
©2002 Foundry Networks, Inc.
MRP – Summary of Benefits
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Fast, sub-second, predictable fail-over functionality
Maximizes ring bandwidth utilization
Cost effective scalable solution for MAN resiliency
Attractive alternative to STP
Utilizes 802.3 Ethernet Packet standards and MACs
Can be combined with other Foundry features to
provide complete end to end MAN designs
©2002 Foundry Networks, Inc.
Virtual Switch Redundancy Protocol
© 2002 Foundry Networks, Inc.
Virtual Switch Redundancy Protocol
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VSRP provides an alternative to Rapid Spanning Tree Protocol
(RSTP) in dual homed/mesh configurations, providing sub-second
fail-over and recovery.
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VSRP features provide:
– Sub-second fail-over
– Efficient use of mesh bandwidth – no blocked links
– Block and unblock ports at the per-VLAN group level
– Large scale L2 MANs with multi-tiered support
– Highly flexible network designs
– Configurable tracking options
– Works with other L2 features
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Works with all Ethernet interfaces, including 10 Gigabit
VSRP is based on VRRP-E & can provide L2 and L3 backup
©2002 Foundry Networks, Inc.
How it works
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VSRP uses an election process to select
a Master switch and up to 4 backup
switches for each VLAN: higher
configured priority wins; if equal, higher
IP address wins.
VSRP
Master
VSRP
Backup
BigIron 8000
Only the Master switch forwards data,
while Backup switches block traffic on
all VSRP configured interfaces within the
VLAN (or the topology group).
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Master switch sends Hello packets to all
backup switches
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Switches do not have to be VSRP aware.
VSRP aware provides faster failover.
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VSRP can track ports and decrease the
priority of VSRP active switch in case a
tracked port goes down.
BigIron 8000
S1
S2
F
F
BigIron 4000
S3
B
F
BigIron 4000
VSRP
Aware
S4
B
B
BigIron 4000
S5
©2002 Foundry Networks, Inc.
Rapid Failover
Master
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A VSRP Backup switch monitors Hellos from
the Master.
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If no Hellos are received for Master Dead
Interval (default 300 ms), Backup goes into
Hold Down state, starts sending periodic
Hellos.
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Hold Down interval is by default 300 ms, and
it allows for the election of a new master.
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If the switch is elected as Master, it sets its
port into forwarding state, sends 3 TCNs.
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A VSRP aware switch receives TCN, and
looks for the new master. Hellos of the new
master will be received on a different port.
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Backup
NetIron 800
A VSRP aware switch shifts the MAC
addresses learned on the failed port to the
new port.
B
FAULT
F
Backup
NetIron 800
NetIron 800
B
NetIron 400
Master
NetIron 800
Dn
Backup
NetIron 800
FAULT
F
NetIron 800
B
NetIron 400
Mac Type:D = Dynamic, S = Static, H = Host, R = Router
MAC
Port
Age Type
0060.f320.23a8
2
0 D
0030.1b07.0694
2
0 D
00d0.b758.88dc
2
0 D
0004.8039.5f00
2
0 D
©2002 Foundry Networks, Inc.
Link Restoration
(Orig. Master)
Backup
Switching Back to Original Master
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Link restored
Master
NetIron 800
When the failed link is restored, the original
Master remains as a Backup.
Original Master receives inferior Hello from
the current Master, so it immediately replies
with its own Hello, switches into Hold Down
state (300 ms), starts sending periodic Hellos
Current Master receives superior Hello, so it
switches into Backup mode.
If no superior Hellos are received during
Hold Down interval, original Master considers
itself the new current Master, and sets its
port in Forwarding mode.
New Master sends out 3 TCNs.
A VSRP aware switch receives TCN, and
looks for the new master. Hellos of the new
master will be received on a different port.
A VSRP aware switch shifts
the MAC addresses to the
new port.
F
B
Backup
NetIron 800
NetIron 800
B
NetIron 400
Master
Backup
NetIron 800
F
Backup
NetIron 800
B
NetIron 800
B
NetIron 400
Mac Type:D = Dynamic, S = Static, H = Host, R = Router
MAC
Port
Age Type
0060.f320.23a8
1
0 D
0030.1b07.0694
1
0 D
00d0.b758.88dc
1
0 D
0004.8039.5f00
1
0 D
©2002 Foundry Networks, Inc.
Efficient use of Uplink Bandwidth
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VSRP supports topology groups to
fully utilize switches and links
Topology groups are a collection of
VLANs
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Each yopology group contains a
Master VLAN and Member VLANs
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VSRP configured switches can be
Master for some topology groups
while backup other for others
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4094 VLANs can be divided among
up to 255 Topology groups
Master topology group 1
Backup topology group 2
BigIron 8000
S1
BigIron 4000
S3
Master topology group 2
Backup topology group 1
Hello
Packets
BigIron 8000
S2
BigIron 4000
VSRP
Aware
S4
BigIron 4000
S5
Topology group 1 = Master VLAN 1
Member VLANs 2 to 2048
Topology group 2 = Master VLAN 2049
Member VLANs 2050 to 4096
©2002 Foundry Networks, Inc.
VSRP Domains
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VSRP can be configured in
separate domains within the same
VLAN to allow for larger
topologies.
NetIron 800
Topology groups can be designed
to use unique paths in each
domain.
VSRP
Domain 1
(VRID 1)
A TTL value within the VSRP Hello
packet controls how deep the
packet goes into the network.
VSRP
Domain 2
(VRID 2)
TTL is being decremented by 1 at
each VSRP aware switch.
Default TTL is 2, which allows
Hello to traverse one VSRP aware
switch to go to another VSRP
active switch.
VSRP
Domain 3
(VRID 3)
NetIron 800
NetIron 800
VSRP
Active
NetIron 400
NetIron 400
VSRP Aware
VSRP Active
NetIron 400
NetIron 400
VSRP Aware
VSRP Active
NetIron 400
NetIron 400
VSRP Aware
©2002 Foundry Networks, Inc.
Intelligent Port Level Control
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VSRP can be configured to run only on
designated ports
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Only VSRP configured ports are placed
in blocking for Backup switches
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Supports host attachments and dual
port NICs: host facing ports are
configured as VSRP free.
•
NetIron 800
NetIron 800
MRP
Master
NetIron 800
Works in combination with MRP to
provide flexible Metro / Enterprise
Ethernet designs.
Backup
NetIron 800
NetIron 400
NetIron 400
VSRP Aware
Dual Homed Servers
©2002 Foundry Networks, Inc.
VSRP-Aware Switches
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Both VSRP-Aware and Non VSRPAware switches can be used as edge
devices
VSRP-Aware switches recognize the
VSRP Hello packet sent by the Master,
and then create an table which
contains the VRID of the VLAN which
sent the VSRP Hello plus the incoming
port where the VSRP Hello was
received.
When the VSRP-Aware switch sees a
Hello packet coming from a different
port, it quickly moves the MAC address
table entries to the new port.
VSRP
Master
VSRP
Backup
BigIron 8000
BigIron 8000
S1
S2
F
F
BigIron 4000
S3
VSRP
Aware
B
F
BigIron 4000
S4
VSRP
Aware
B
B
BigIron 4000
S5
VSRP
Aware
©2002 Foundry Networks, Inc.
Non VSRP-Aware Switches
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Non VSRP-Aware switches can be used
as edge devices, but they do not
recognize VSRP Hello packets.
MAC entries will age out or they will
eventually be learned from the new
port.
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This results in slow convergence when
the Master fails.
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Solution is to configure “VSRP Fast
Start” in the VSRP Master and Backup
nodes.
•
VSRP
Master
VSRP
Backup
BigIron 8000
BigIron 8000
S1
S2
F
F
BigIron 4000
S3
Non VSRP
Aware
B
F
BigIron 4000
S4
Non VSRP
Aware
B
B
BigIron 4000
S5
Non VSRP
Aware
VSRP Fast Start disables and re-enable
the ports before transitioning from
Master to Backup. This causes a MAC
address flush in the edge devices
which makes convergence faster.
©2002 Foundry Networks, Inc.
VSRP – Summary of Benefits
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Fast, sub-second protection without Spanning Tree
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Supports topology groups for full link utilization
Combines both switching and routing redundancy
– Provides default gateway redundancy if needed
Can be combined with other Foundry features to
provide complete end to end MAN designs
©2002 Foundry Networks, Inc.
References
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LINX - https://www.linx.net/
AMS-IX - http://www.ams-ix.net/
“I can feel your traffic” - http://www.jasinska.de/
MRP- http://www.foundrynet.com/pdf/wp-mrp.pdf
VSRP - http://www.foundrynet.com/pdf/wp-vsrp.pdf
©2002 Foundry Networks, Inc.
Thank You !
Marcelo Molinari – Foundry Networks do Brasil
[email protected]
© 2002 Foundry Networks, Inc.