Brocade Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide (Supporting R05.6.00) - Manual (Page 195)

Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide 171
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Dynamic Bypass LSPs
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• Now the first dynamic bypass has nine megabits per second and the second dynamic bypass
has one megabyte per second occupied and there are 10 backup paths. Look at this at a
bandwidth use optimization point of view; all 10 backups are accommodated in only one
dynamic bypass LSP. Having an algorithm which realigns the backups so there is only one
dynamic bypass, instead of two bypasses is not supported in this release.
• All dynamic bypass creation or reuse by a protected path depends on the protected LSP
backup path request triggers. This means a backup path established over a dynamic bypass
depends on a protected path request and retries.
• Node or link protection attributes are signaled through the session attributes of the protected
LSP. Based on the protected path requested backup protection type, node or link protection
dynamic bypasses are created.
• Deciding on a possible merge point from a PLR on an existing dynamic bypass LSP depends on
the existing backup path re-setup mechanism. A failure in the existing dynamic bypass LSP
leads to a new backup retry from a protected LSP PLR and is considered as new backup path
setup sequence.
• Dynamic bypass LSP functionality as a bypass LSP is by way of an existing bypass LSP. All timer
driven or user initiated re-optimization MBB is the same as the existing bypass LSP MBB.
• Dynamic bypass LSP modification (make-before-break) is not allowed, except for a case of
re-optimization. When a new protected LSP requests more bandwidth, no automatic MBB is
performed for the existing dynamic bypass LSP. Re-optimization makes use of
make-before-break, to modify the LSP, so it can create the new instance of the dynamic bypass
LSP. The newly created dynamic bypass LSP uses the latest attributes from the global and
interface level dynamic bypass configurations. Re-optimization is carried out upon a
re-optimization timer expiry.
• The total number of bypass LSPs that are created on a device is limited to 1000. This is due to
an existing limitation relating to number and content of next-hop entries. This limit of 1000 is
applicable for the cumulative total of both the static and dynamic bypass LSPs. Therefore, the
maximum number of dynamic bypass LSPs created on a system is always equal to (1000 –
(current number of configured static bypass LSPs)).
• Dynamic bypass optimization with a modified bandwidth is performed using MBB during the
optimization process (timer expiry or user initiated). No detour or backup re-optimization to
minimize dynamic bypass LSPs is completed in this release.
• Dynamic bypass interface mean bandwidth validation with MPLS interface maximum or
reservable bandwidth is not completed because MPLS interface bandwidth changes
dynamically based on configurations like LAG.
Creating a dynamic bypass LSP
The dynamic bypass LSP feature is activated by enabling the dynamic bypass at the global level
under the router MPLS and dynamic-bypass.
Dynamic bypass LSP creation is controlled by a combination of control at global level and the
interface level. A MPLS interface with dynamic bypass enabled is able to create dynamic bypass
LSP to provide backup path for protected LSP traversing out of this interface. Refer to
Figure 25 for
creating a dynamic bypass LSP.
FIGURE 25 Creating a dynamic bypass LSP